From cc8aa7d2d6ec0cb9d0b1b0ff7b9d2d2094e51eb1 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Mon, 18 Dec 2023 03:12:59 -0800
Subject: [PATCH 01/19] Fix `getTimezoneOffset()` when `tm_gmtoff` is not
 available

In my environment, the build fails because `tm_gmtoff` is not available:

```
quickjs.c: In function 'getTimezoneOffset':
quickjs.c:40527:15: error: 'struct tm' has no member named 'tm_gmtoff'
40527 |     return -tm.tm_gmtoff / 60;
      |               ^
```

This approach attempts to reimplement the `getTimezoneOffset()` to not
rely on that property. This change works for my build environment, but
I am open to any suggestions for improvement.

I didn't test, but this might also work on Windows where this logic is
currently not implemented.
---
 quickjs.c | 54 +++++++++++++++++++++++-------------------------------
 1 file changed, 23 insertions(+), 31 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index 0c02b5675..cb507d6a0 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40493,38 +40493,31 @@ static const JSCFunctionListEntry js_math_obj[] = {
 
 /* OS dependent. d = argv[0] is in ms from 1970. Return the difference
    between UTC time and local time 'd' in minutes */
-static int getTimezoneOffset(int64_t time) {
+static int getTimezoneOffset() {
 #if defined(_WIN32)
     /* XXX: TODO */
     return 0;
 #else
-    time_t ti;
-    struct tm tm;
-
-    time /= 1000; /* convert to seconds */
-    if (sizeof(time_t) == 4) {
-        /* on 32-bit systems, we need to clamp the time value to the
-           range of `time_t`. This is better than truncating values to
-           32 bits and hopefully provides the same result as 64-bit
-           implementation of localtime_r.
-         */
-        if ((time_t)-1 < 0) {
-            if (time < INT32_MIN) {
-                time = INT32_MIN;
-            } else if (time > INT32_MAX) {
-                time = INT32_MAX;
-            }
-        } else {
-            if (time < 0) {
-                time = 0;
-            } else if (time > UINT32_MAX) {
-                time = UINT32_MAX;
-            }
-        }
+    time_t unixTime = time(NULL);
+
+    struct tm* localTime = localtime(&unixTime);
+    time_t localTimeNum = mktime(localTime);
+
+    struct tm *gmtTime = gmtime(&unixTime);
+    time_t gmtTimeNum = mktime(gmtTime);
+
+    // Calculate the time zone offset in minutes
+    int timeZoneOffset = (int)difftime(localTimeNum, gmtTimeNum) / 60;
+
+    // In JavaScript, it's the opposite
+    timeZoneOffset = -timeZoneOffset;
+
+    // Take off another hour if daylight savings it active
+    if (localTime->tm_isdst) {
+        timeZoneOffset = timeZoneOffset - 60;
     }
-    ti = time;
-    localtime_r(&ti, &tm);
-    return -tm.tm_gmtoff / 60;
+
+    return timeZoneOffset;
 #endif
 }
 
@@ -46531,7 +46524,7 @@ static __exception int get_date_fields(JSContext *ctx, JSValue obj,
     } else {
         d = dval;
         if (is_local) {
-            tz = -getTimezoneOffset(d);
+            tz = -getTimezoneOffset();
             d += tz * 60000;
         }
     }
@@ -46600,7 +46593,7 @@ static double set_date_fields(double fields[], int is_local) {
         fields[5] * 1000 + fields[6];
     d = days * 86400000 + h;
     if (is_local)
-        d += getTimezoneOffset(d) * 60000;
+        d += getTimezoneOffset() * 60000;
     return time_clip(d);
 }
 
@@ -47203,7 +47196,6 @@ static JSValue js_date_Symbol_toPrimitive(JSContext *ctx, JSValue this_val,
 static JSValue js_date_getTimezoneOffset(JSContext *ctx, JSValue this_val,
                                          int argc, JSValue *argv)
 {
-    // getTimezoneOffset()
     double v;
 
     if (JS_ThisTimeValue(ctx, &v, this_val))
@@ -47211,7 +47203,7 @@ static JSValue js_date_getTimezoneOffset(JSContext *ctx, JSValue this_val,
     if (isnan(v))
         return JS_NAN;
     else
-        return JS_NewInt64(ctx, getTimezoneOffset((int64_t)trunc(v)));
+        return JS_NewInt64(ctx, getTimezoneOffset());
 }
 
 static JSValue js_date_getTime(JSContext *ctx, JSValue this_val,

From 181932980944fe446b0a165170830a40c7cb9ced Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Mon, 18 Dec 2023 17:00:01 -0800
Subject: [PATCH 02/19] Simplify

---
 quickjs.c | 35 ++++++-----------------------------
 1 file changed, 6 insertions(+), 29 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index cb507d6a0..7321104d1 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40493,32 +40493,9 @@ static const JSCFunctionListEntry js_math_obj[] = {
 
 /* OS dependent. d = argv[0] is in ms from 1970. Return the difference
    between UTC time and local time 'd' in minutes */
-static int getTimezoneOffset() {
-#if defined(_WIN32)
-    /* XXX: TODO */
-    return 0;
-#else
-    time_t unixTime = time(NULL);
-
-    struct tm* localTime = localtime(&unixTime);
-    time_t localTimeNum = mktime(localTime);
-
-    struct tm *gmtTime = gmtime(&unixTime);
-    time_t gmtTimeNum = mktime(gmtTime);
-
-    // Calculate the time zone offset in minutes
-    int timeZoneOffset = (int)difftime(localTimeNum, gmtTimeNum) / 60;
-
-    // In JavaScript, it's the opposite
-    timeZoneOffset = -timeZoneOffset;
-
-    // Take off another hour if daylight savings it active
-    if (localTime->tm_isdst) {
-        timeZoneOffset = timeZoneOffset - 60;
-    }
-
-    return timeZoneOffset;
-#endif
+static int getTimezoneOffset(int64_t time) {
+    struct tm *gmt = gmtime((const time_t *)&time);
+    return (mktime(gmt) - time) / 60;
 }
 
 /* RegExp */
@@ -46524,7 +46501,7 @@ static __exception int get_date_fields(JSContext *ctx, JSValue obj,
     } else {
         d = dval;
         if (is_local) {
-            tz = -getTimezoneOffset();
+            tz = -getTimezoneOffset(d);
             d += tz * 60000;
         }
     }
@@ -46593,7 +46570,7 @@ static double set_date_fields(double fields[], int is_local) {
         fields[5] * 1000 + fields[6];
     d = days * 86400000 + h;
     if (is_local)
-        d += getTimezoneOffset() * 60000;
+        d += getTimezoneOffset(d) * 60000;
     return time_clip(d);
 }
 
@@ -47203,7 +47180,7 @@ static JSValue js_date_getTimezoneOffset(JSContext *ctx, JSValue this_val,
     if (isnan(v))
         return JS_NAN;
     else
-        return JS_NewInt64(ctx, getTimezoneOffset());
+        return JS_NewInt64(ctx, getTimezoneOffset((int64_t)trunc(v)));
 }
 
 static JSValue js_date_getTime(JSContext *ctx, JSValue this_val,

From fe049ff5b84d3c06bf6a6d2ff497a6f62db67404 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Mon, 18 Dec 2023 17:17:03 -0800
Subject: [PATCH 03/19] Add timezone adjustment

---
 quickjs.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index 7321104d1..6d916f218 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40494,8 +40494,19 @@ static const JSCFunctionListEntry js_math_obj[] = {
 /* OS dependent. d = argv[0] is in ms from 1970. Return the difference
    between UTC time and local time 'd' in minutes */
 static int getTimezoneOffset(int64_t time) {
-    struct tm *gmt = gmtime((const time_t *)&time);
-    return (mktime(gmt) - time) / 60;
+    struct tm local;
+    struct tm gmt;
+    time /= 1000; /* convert to seconds */
+    localtime_r((const time_t *)&time, &local);
+    gmtime_r((const time_t *)&time, &gmt);
+    int offset = (mktime(&gmt) - time) / 60;
+
+    /* take off another hour if daylight savings is active */
+    if (local.tm_isdst) {
+        offset -= 60;
+    }
+
+    return offset;
 }
 
 /* RegExp */

From 8ad0bb8ea2571c340f6414c11efbda08a4c76c4d Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Mon, 18 Dec 2023 17:25:20 -0800
Subject: [PATCH 04/19] Minimize diff

---
 quickjs.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index 6d916f218..27b5b9c44 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40494,12 +40494,38 @@ static const JSCFunctionListEntry js_math_obj[] = {
 /* OS dependent. d = argv[0] is in ms from 1970. Return the difference
    between UTC time and local time 'd' in minutes */
 static int getTimezoneOffset(int64_t time) {
-    struct tm local;
+#if defined(_WIN32)
+    /* XXX: TODO */
+    return 0;
+#else
+    time_t ti;
     struct tm gmt;
+    struct tm local;
     time /= 1000; /* convert to seconds */
-    localtime_r((const time_t *)&time, &local);
-    gmtime_r((const time_t *)&time, &gmt);
-    int offset = (mktime(&gmt) - time) / 60;
+    if (sizeof(time_t) == 4) {
+        /* on 32-bit systems, we need to clamp the time value to the
+           range of `time_t`. This is better than truncating values to
+           32 bits and hopefully provides the same result as 64-bit
+           implementation of localtime_r.
+         */
+        if ((time_t)-1 < 0) {
+            if (time < INT32_MIN) {
+                time = INT32_MIN;
+            } else if (time > INT32_MAX) {
+                time = INT32_MAX;
+            }
+        } else {
+            if (time < 0) {
+                time = 0;
+            } else if (time > UINT32_MAX) {
+                time = UINT32_MAX;
+            }
+        }
+    }
+    ti = time;
+    localtime_r(&ti, &local);
+    gmtime_r(&ti, &gmt);
+    int offset = (mktime(&gmt) - ti) / 60;
 
     /* take off another hour if daylight savings is active */
     if (local.tm_isdst) {
@@ -40507,6 +40533,7 @@ static int getTimezoneOffset(int64_t time) {
     }
 
     return offset;
+#endif
 }
 
 /* RegExp */

From 2871afbd423eddcb5ae1934c10d472589b4417a6 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Mon, 18 Dec 2023 17:59:22 -0800
Subject: [PATCH 05/19] .

---
 quickjs.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index 27b5b9c44..b4d2bf07b 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40499,8 +40499,8 @@ static int getTimezoneOffset(int64_t time) {
     return 0;
 #else
     time_t ti;
+    struct tm tm;
     struct tm gmt;
-    struct tm local;
     time /= 1000; /* convert to seconds */
     if (sizeof(time_t) == 4) {
         /* on 32-bit systems, we need to clamp the time value to the
@@ -40523,12 +40523,12 @@ static int getTimezoneOffset(int64_t time) {
         }
     }
     ti = time;
-    localtime_r(&ti, &local);
+    localtime_r(&ti, &tm);
     gmtime_r(&ti, &gmt);
     int offset = (mktime(&gmt) - ti) / 60;
 
     /* take off another hour if daylight savings is active */
-    if (local.tm_isdst) {
+    if (tm.tm_isdst) {
         offset -= 60;
     }
 

From 016903800f12cb8b36f5f2c77f8be704a71e0968 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Mon, 18 Dec 2023 18:00:02 -0800
Subject: [PATCH 06/19] .

---
 quickjs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/quickjs.c b/quickjs.c
index b4d2bf07b..9de928e78 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -47211,6 +47211,7 @@ static JSValue js_date_Symbol_toPrimitive(JSContext *ctx, JSValue this_val,
 static JSValue js_date_getTimezoneOffset(JSContext *ctx, JSValue this_val,
                                          int argc, JSValue *argv)
 {
+    // getTimezoneOffset()
     double v;
 
     if (JS_ThisTimeValue(ctx, &v, this_val))

From 162082c4af43b8fa2d2fd090735c9c082a1993b3 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Wed, 20 Dec 2023 15:42:32 -0800
Subject: [PATCH 07/19] Remove manual dst adjustment

---
 quickjs.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index 9de928e78..7ff8fdb8c 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40525,14 +40525,11 @@ static int getTimezoneOffset(int64_t time) {
     ti = time;
     localtime_r(&ti, &tm);
     gmtime_r(&ti, &gmt);
-    int offset = (mktime(&gmt) - ti) / 60;
 
-    /* take off another hour if daylight savings is active */
-    if (tm.tm_isdst) {
-        offset -= 60;
-    }
+    /* adjust the gmt struct to represent local time */
+    gmt.tm_isdst = tm.tm_isdst;
 
-    return offset;
+    return difftime(mktime(&gmt), mktime(&tm)) / 60;
 #endif
 }
 

From 978a145cf2832008b52d068e09d86c478fb231d5 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Wed, 20 Dec 2023 16:05:55 -0800
Subject: [PATCH 08/19] Use CMake to check if `tm_gmtoff` exists

---
 .gitignore     | 1 +
 CMakeLists.txt | 4 ++++
 config.h.in    | 1 +
 quickjs.c      | 7 ++++++-
 4 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 config.h.in

diff --git a/.gitignore b/.gitignore
index a1aae7192..989526fc2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@
 build/
 unicode/
 test262_*.txt
+config.h
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2d7eaf5f8..b0ee3e23b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,6 +3,7 @@ cmake_minimum_required(VERSION 3.9)
 project(quickjs LANGUAGES C)
 
 include(CheckCCompilerFlag)
+include(CheckStructHasMember)
 include(GNUInstallDirs)
 
 # TODO:
@@ -63,6 +64,9 @@ if(CMAKE_BUILD_TYPE MATCHES "Debug")
     xcheck_add_c_compiler_flag(-fno-omit-frame-pointer)
 endif()
 
+check_struct_has_member("struct tm" tm_gmtoff "time.h" HAVE_TM_GMTOFF LANGUAGE C)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in ${CMAKE_CURRENT_SOURCE_DIR}/config.h)
+
 macro(xoption OPTION_NAME OPTION_TEXT OPTION_DEFAULT)
     option(${OPTION_NAME} ${OPTION_TEXT} ${OPTION_DEFAULT})
     if(DEFINED ENV{${OPTION_NAME}})
diff --git a/config.h.in b/config.h.in
new file mode 100644
index 000000000..771cda44c
--- /dev/null
+++ b/config.h.in
@@ -0,0 +1 @@
+#cmakedefine HAVE_TM_GMTOFF
diff --git a/quickjs.c b/quickjs.c
index 7ff8fdb8c..8a7248f37 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -42,6 +42,7 @@
 #include "quickjs.h"
 #include "libregexp.h"
 #include "libbf.h"
+#include "config.h"
 
 #if defined(EMSCRIPTEN) || defined(_MSC_VER)
 #define DIRECT_DISPATCH  0
@@ -40500,7 +40501,6 @@ static int getTimezoneOffset(int64_t time) {
 #else
     time_t ti;
     struct tm tm;
-    struct tm gmt;
     time /= 1000; /* convert to seconds */
     if (sizeof(time_t) == 4) {
         /* on 32-bit systems, we need to clamp the time value to the
@@ -40524,12 +40524,17 @@ static int getTimezoneOffset(int64_t time) {
     }
     ti = time;
     localtime_r(&ti, &tm);
+#ifdef HAVE_TM_GMTOFF
+    return -tm.tm_gmtoff / 60;
+#else
+    struct tm gmt;
     gmtime_r(&ti, &gmt);
 
     /* adjust the gmt struct to represent local time */
     gmt.tm_isdst = tm.tm_isdst;
 
     return difftime(mktime(&gmt), mktime(&tm)) / 60;
+#endif /* HAVE_TM_GMTOFF */
 #endif
 }
 

From e397c3671a0aa20055146ab78e5a11277f0c9478 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Wed, 20 Dec 2023 16:20:36 -0800
Subject: [PATCH 09/19] .

---
 quickjs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/quickjs.c b/quickjs.c
index 8a7248f37..3ee8aee89 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40501,6 +40501,7 @@ static int getTimezoneOffset(int64_t time) {
 #else
     time_t ti;
     struct tm tm;
+
     time /= 1000; /* convert to seconds */
     if (sizeof(time_t) == 4) {
         /* on 32-bit systems, we need to clamp the time value to the

From c257fc0e004833c95b727759a1d282ba85bff82b Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Thu, 21 Dec 2023 01:24:17 -0800
Subject: [PATCH 10/19] Switch to -D define instead of `config.h`

---
 .gitignore     | 1 -
 CMakeLists.txt | 4 +++-
 config.h.in    | 1 -
 quickjs.c      | 1 -
 4 files changed, 3 insertions(+), 4 deletions(-)
 delete mode 100644 config.h.in

diff --git a/.gitignore b/.gitignore
index 989526fc2..a1aae7192 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,4 +5,3 @@
 build/
 unicode/
 test262_*.txt
-config.h
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b0ee3e23b..e62a142dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,7 +65,9 @@ if(CMAKE_BUILD_TYPE MATCHES "Debug")
 endif()
 
 check_struct_has_member("struct tm" tm_gmtoff "time.h" HAVE_TM_GMTOFF LANGUAGE C)
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in ${CMAKE_CURRENT_SOURCE_DIR}/config.h)
+if(HAVE_TM_GMTOFF)
+    add_compile_definitions(HAVE_TM_GMTOFF)
+endif()
 
 macro(xoption OPTION_NAME OPTION_TEXT OPTION_DEFAULT)
     option(${OPTION_NAME} ${OPTION_TEXT} ${OPTION_DEFAULT})
diff --git a/config.h.in b/config.h.in
deleted file mode 100644
index 771cda44c..000000000
--- a/config.h.in
+++ /dev/null
@@ -1 +0,0 @@
-#cmakedefine HAVE_TM_GMTOFF
diff --git a/quickjs.c b/quickjs.c
index 3ee8aee89..0b03affa3 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -42,7 +42,6 @@
 #include "quickjs.h"
 #include "libregexp.h"
 #include "libbf.h"
-#include "config.h"
 
 #if defined(EMSCRIPTEN) || defined(_MSC_VER)
 #define DIRECT_DISPATCH  0

From 9bb0a1551c5bc6f25348493d110f15c1cb32d843 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Thu, 21 Dec 2023 02:24:53 -0800
Subject: [PATCH 11/19] Disable DST on local struct

---
 quickjs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index 0b03affa3..2eeb9cf8c 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -40530,8 +40530,8 @@ static int getTimezoneOffset(int64_t time) {
     struct tm gmt;
     gmtime_r(&ti, &gmt);
 
-    /* adjust the gmt struct to represent local time */
-    gmt.tm_isdst = tm.tm_isdst;
+    /* disable DST adjustment on the local tm struct */
+    tm.tm_isdst = 0;
 
     return difftime(mktime(&gmt), mktime(&tm)) / 60;
 #endif /* HAVE_TM_GMTOFF */

From cb0e4ffe6768b39fbeabd2c74a79ef4d92d9f774 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 00:41:14 -0800
Subject: [PATCH 12/19] Remove auto-detection, use explicit flag and enable for
 newlib by default

---
 CMakeLists.txt | 10 +++++-----
 quickjs.c      | 14 ++++++++++----
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e62a142dc..37ce67122 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -64,11 +64,6 @@ if(CMAKE_BUILD_TYPE MATCHES "Debug")
     xcheck_add_c_compiler_flag(-fno-omit-frame-pointer)
 endif()
 
-check_struct_has_member("struct tm" tm_gmtoff "time.h" HAVE_TM_GMTOFF LANGUAGE C)
-if(HAVE_TM_GMTOFF)
-    add_compile_definitions(HAVE_TM_GMTOFF)
-endif()
-
 macro(xoption OPTION_NAME OPTION_TEXT OPTION_DEFAULT)
     option(${OPTION_NAME} ${OPTION_TEXT} ${OPTION_DEFAULT})
     if(DEFINED ENV{${OPTION_NAME}})
@@ -91,6 +86,11 @@ xoption(BUILD_STATIC_QJS_EXE "Build a static qjs executable" OFF)
 xoption(CONFIG_ASAN "Enable AddressSanitizer (ASan)" OFF)
 xoption(CONFIG_MSAN "Enable MemorySanitizer (MSan)" OFF)
 xoption(CONFIG_UBSAN "Enable UndefinedBehaviorSanitizer (UBSan)" OFF)
+xoption(CONFIG_TM_GMTOFF "Enable when `tm_gmtoff` exists on `struct tm` " ON)
+
+if(NOT CONFIG_TM_GMTOFF)
+    add_compile_definitions(NO_TM_GMTOFF)
+endif()
 
 if(CONFIG_ASAN)
 message(STATUS "Building with ASan")
diff --git a/quickjs.c b/quickjs.c
index 2eeb9cf8c..3fa8a1c7d 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -60,6 +60,12 @@
 #define CONFIG_PRINTF_RNDN
 #endif
 
+#if defined(_NEWLIB_STDIO_H)
+/* define if `struct tm` does not contain `tm_gmtoff` property */
+/* this can also be enabled through `cmake -DCONFIG_TM_GMTOFF=OFF  */
+#define NO_TM_GMTOFF
+#endif
+
 /* dump object free */
 //#define DUMP_FREE
 //#define DUMP_CLOSURE
@@ -40524,9 +40530,7 @@ static int getTimezoneOffset(int64_t time) {
     }
     ti = time;
     localtime_r(&ti, &tm);
-#ifdef HAVE_TM_GMTOFF
-    return -tm.tm_gmtoff / 60;
-#else
+#ifdef NO_TM_GMTOFF
     struct tm gmt;
     gmtime_r(&ti, &gmt);
 
@@ -40534,7 +40538,9 @@ static int getTimezoneOffset(int64_t time) {
     tm.tm_isdst = 0;
 
     return difftime(mktime(&gmt), mktime(&tm)) / 60;
-#endif /* HAVE_TM_GMTOFF */
+#else
+    return -tm.tm_gmtoff / 60;
+#endif /* NO_TM_GMTOFF */
 #endif
 }
 

From ebb4d7906d60b40b9a31b73f79b54b6d46c4a24e Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 01:07:16 -0800
Subject: [PATCH 13/19] Check for `__NEWLIB__`

---
 quickjs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/quickjs.c b/quickjs.c
index 3fa8a1c7d..78708309c 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -60,7 +60,7 @@
 #define CONFIG_PRINTF_RNDN
 #endif
 
-#if defined(_NEWLIB_STDIO_H)
+#if defined(__NEWLIB__)
 /* define if `struct tm` does not contain `tm_gmtoff` property */
 /* this can also be enabled through `cmake -DCONFIG_TM_GMTOFF=OFF  */
 #define NO_TM_GMTOFF

From c522d1dfb24693bc2e22c8e7af718bccf42eb589 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 01:14:24 -0800
Subject: [PATCH 14/19] Simplify

---
 CMakeLists.txt |  6 +-----
 quickjs.c      | 14 +++++++-------
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 37ce67122..56da92ebd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -86,11 +86,7 @@ xoption(BUILD_STATIC_QJS_EXE "Build a static qjs executable" OFF)
 xoption(CONFIG_ASAN "Enable AddressSanitizer (ASan)" OFF)
 xoption(CONFIG_MSAN "Enable MemorySanitizer (MSan)" OFF)
 xoption(CONFIG_UBSAN "Enable UndefinedBehaviorSanitizer (UBSan)" OFF)
-xoption(CONFIG_TM_GMTOFF "Enable when `tm_gmtoff` exists on `struct tm` " ON)
-
-if(NOT CONFIG_TM_GMTOFF)
-    add_compile_definitions(NO_TM_GMTOFF)
-endif()
+xoption(HAVE_TM_GMTOFF "Enable when `tm_gmtoff` exists on `struct tm` " ON)
 
 if(CONFIG_ASAN)
 message(STATUS "Building with ASan")
diff --git a/quickjs.c b/quickjs.c
index 78708309c..41e61a994 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -61,9 +61,9 @@
 #endif
 
 #if defined(__NEWLIB__)
-/* define if `struct tm` does not contain `tm_gmtoff` property */
-/* this can also be enabled through `cmake -DCONFIG_TM_GMTOFF=OFF  */
-#define NO_TM_GMTOFF
+/* undefine if `struct tm` does not contain `tm_gmtoff` property */
+/* this can also be configured through `cmake -DHAVE_TM_GMTOFF=OFF  */
+#undef HAVE_TM_GMTOFF
 #endif
 
 /* dump object free */
@@ -40530,7 +40530,9 @@ static int getTimezoneOffset(int64_t time) {
     }
     ti = time;
     localtime_r(&ti, &tm);
-#ifdef NO_TM_GMTOFF
+#ifdef HAVE_TM_GMTOFF
+    return -tm.tm_gmtoff / 60;
+#else
     struct tm gmt;
     gmtime_r(&ti, &gmt);
 
@@ -40538,9 +40540,7 @@ static int getTimezoneOffset(int64_t time) {
     tm.tm_isdst = 0;
 
     return difftime(mktime(&gmt), mktime(&tm)) / 60;
-#else
-    return -tm.tm_gmtoff / 60;
-#endif /* NO_TM_GMTOFF */
+#endif /* HAVE_TM_GMTOFF */
 #endif
 }
 

From 28614118219f979a598c03d64881319c7c75c161 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 01:15:16 -0800
Subject: [PATCH 15/19] .

---
 CMakeLists.txt | 1 -
 1 file changed, 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 56da92ebd..d7172be64 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,6 @@ cmake_minimum_required(VERSION 3.9)
 project(quickjs LANGUAGES C)
 
 include(CheckCCompilerFlag)
-include(CheckStructHasMember)
 include(GNUInstallDirs)
 
 # TODO:

From 86e13f234399bcf7819f41c89466b61a8aa89bc8 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 01:17:36 -0800
Subject: [PATCH 16/19] .

---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d7172be64..b9bb0b52d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -85,7 +85,7 @@ xoption(BUILD_STATIC_QJS_EXE "Build a static qjs executable" OFF)
 xoption(CONFIG_ASAN "Enable AddressSanitizer (ASan)" OFF)
 xoption(CONFIG_MSAN "Enable MemorySanitizer (MSan)" OFF)
 xoption(CONFIG_UBSAN "Enable UndefinedBehaviorSanitizer (UBSan)" OFF)
-xoption(HAVE_TM_GMTOFF "Enable when `tm_gmtoff` exists on `struct tm` " ON)
+xoption(HAVE_TM_GMTOFF "Enable when `tm_gmtoff` exists on `struct tm`" ON)
 
 if(CONFIG_ASAN)
 message(STATUS "Building with ASan")

From da5db5e100975dcee7340fd7cda74f5fb060ed38 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 03:29:59 -0800
Subject: [PATCH 17/19] Remove unnecessary comments

---
 quickjs.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/quickjs.c b/quickjs.c
index 41e61a994..8a7259150 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -61,8 +61,6 @@
 #endif
 
 #if defined(__NEWLIB__)
-/* undefine if `struct tm` does not contain `tm_gmtoff` property */
-/* this can also be configured through `cmake -DHAVE_TM_GMTOFF=OFF  */
 #undef HAVE_TM_GMTOFF
 #endif
 

From 4c4d73dd325935d1c6699a7b1a8024e0c1644e0f Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 23:51:30 -0800
Subject: [PATCH 18/19] Remove CMake option

---
 CMakeLists.txt |  1 -
 quickjs.c      | 10 +++++-----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b9bb0b52d..2d7eaf5f8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -85,7 +85,6 @@ xoption(BUILD_STATIC_QJS_EXE "Build a static qjs executable" OFF)
 xoption(CONFIG_ASAN "Enable AddressSanitizer (ASan)" OFF)
 xoption(CONFIG_MSAN "Enable MemorySanitizer (MSan)" OFF)
 xoption(CONFIG_UBSAN "Enable UndefinedBehaviorSanitizer (UBSan)" OFF)
-xoption(HAVE_TM_GMTOFF "Enable when `tm_gmtoff` exists on `struct tm`" ON)
 
 if(CONFIG_ASAN)
 message(STATUS "Building with ASan")
diff --git a/quickjs.c b/quickjs.c
index 8a7259150..829d5a294 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -61,7 +61,7 @@
 #endif
 
 #if defined(__NEWLIB__)
-#undef HAVE_TM_GMTOFF
+#undef NO_TM_GMTOFF
 #endif
 
 /* dump object free */
@@ -40528,9 +40528,7 @@ static int getTimezoneOffset(int64_t time) {
     }
     ti = time;
     localtime_r(&ti, &tm);
-#ifdef HAVE_TM_GMTOFF
-    return -tm.tm_gmtoff / 60;
-#else
+#ifdef NO_TM_GMTOFF
     struct tm gmt;
     gmtime_r(&ti, &gmt);
 
@@ -40538,7 +40536,9 @@ static int getTimezoneOffset(int64_t time) {
     tm.tm_isdst = 0;
 
     return difftime(mktime(&gmt), mktime(&tm)) / 60;
-#endif /* HAVE_TM_GMTOFF */
+#else
+    return -tm.tm_gmtoff / 60;
+#endif /* NO_TM_GMTOFF */
 #endif
 }
 

From 9cac51cc150c730b79ad1771af34cf89d9fb7cd6 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sat, 23 Dec 2023 23:53:29 -0800
Subject: [PATCH 19/19] .

---
 quickjs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/quickjs.c b/quickjs.c
index 829d5a294..43bb36c97 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -61,7 +61,7 @@
 #endif
 
 #if defined(__NEWLIB__)
-#undef NO_TM_GMTOFF
+#define NO_TM_GMTOFF
 #endif
 
 /* dump object free */