[lldb] Fix printf formatting of std::time_t seconds

This formatter
llvm#78609
was originally passing the signed seconds (which can refer to times
in the past) with an unsigned printf formatter, and had tests that
expected to see negative values from the printf which always failed
on macOS.  I'm not clear how they ever passed on any platform.

Fix the printf to print seconds as a signed value, and re-enable
the tests.

Author: jasonmolenda

lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp

@@ -1105,16 +1105,16 @@ bool lldb_private::formatters::LibcxxChronoSysSecondsSummaryProvider(
 
   const std::time_t seconds = ptr_sp->GetValueAsSigned(0);
   if (seconds < chrono_timestamp_min || seconds > chrono_timestamp_max)
-    stream.Printf("timestamp=%" PRIu64 " s", static_cast<uint64_t>(seconds));
+    stream.Printf("timestamp=%" PRId64 " s", static_cast<int64_t>(seconds));
   else {
     std::array<char, 128> str;
     std::size_t size =
         std::strftime(str.data(), str.size(), "%FT%H:%M:%SZ", gmtime(&seconds));
     if (size == 0)
       return false;
 
-    stream.Printf("date/time=%s timestamp=%" PRIu64 " s", str.data(),
-                  static_cast<uint64_t>(seconds));
+    stream.Printf("date/time=%s timestamp=%" PRId64 " s", str.data(),
+                  static_cast<int64_t>(seconds));
   }
 
   return true;

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/chrono/TestDataFormatterLibcxxChrono.py

@@ -54,17 +54,16 @@ def test_with_run_command(self):
             substrs=["ss_0 = date/time=1970-01-01T00:00:00Z timestamp=0 s"],
         )
 
-        # FIXME disabled temporarily, macOS is printing this as an unsigned?
-        #self.expect(
-        #    "frame variable ss_neg_date_time",
-        #    substrs=[
-        #        "ss_neg_date_time = date/time=-32767-01-01T00:00:00Z timestamp=-1096193779200 s"
-        #    ],
-        #)
-        #self.expect(
-        #    "frame variable ss_neg_seconds",
-        #    substrs=["ss_neg_seconds = timestamp=-1096193779201 s"],
-        #)
+        self.expect(
+            "frame variable ss_neg_date_time",
+            substrs=[
+                "ss_neg_date_time = date/time=-32767-01-01T00:00:00Z timestamp=-1096193779200 s"
+            ],
+        )
+        self.expect(
+            "frame variable ss_neg_seconds",
+            substrs=["ss_neg_seconds = timestamp=-1096193779201 s"],
+        )
 
         self.expect(
             "frame variable ss_pos_date_time",
@@ -77,11 +76,10 @@ def test_with_run_command(self):
             substrs=["ss_pos_seconds = timestamp=971890963200 s"],
         )
 
-        # FIXME disabled temporarily, macOS is printing this as an unsigned?
-        #self.expect(
-        #    "frame variable ss_min",
-        #    substrs=["ss_min = timestamp=-9223372036854775808 s"],
-        #)
+        self.expect(
+            "frame variable ss_min",
+            substrs=["ss_min = timestamp=-9223372036854775808 s"],
+        )
         self.expect(
             "frame variable ss_max",
             substrs=["ss_max = timestamp=9223372036854775807 s"],