Remove HAVE_SIGNAL_H

The `<signal.h>` header file is part of the standard C89 headers [1] and
on current systems can be included unconditionally.

Since file requires at least C89 or greater, the `HAVE_SIGNAL_H` symbol
defined by Autoconf in Zend.m4 [2] can be ommitted and simplifed.

The bundled libmagic (file) also ommits the usage of HAVE_SIGNAL_H since
5.35 however current version in PHP is very modified 5.34 version and
will be refactored separately. Check for HAVE_SIGNAL_H is therefore
still done in the configure.ac.

Refs:
[1] https://port70.net/~nsz/c/c89/c89-draft.html#4.1.2
[2] https://git.savannah.gnu.org/cgit/autoconf.git/tree/lib/autoconf/headers.m4

Author: petk

TSRM/TSRM.h

@@ -82,9 +82,7 @@ typedef int ts_rsrc_id;
 # define MUTEX_T st_mutex_t
 #endif
 
-#ifdef HAVE_SIGNAL_H
 #include <signal.h>
-#endif
 
 typedef void (*ts_allocate_ctor)(void *);
 typedef void (*ts_allocate_dtor)(void *);

Zend/Zend.m4

@@ -12,7 +12,6 @@ malloc.h \
 unistd.h \
 sys/types.h \
 sys/time.h \
-signal.h \
 unix.h \
 cpuid.h \
 dlfcn.h)

Zend/zend_alloc.c

@@ -57,10 +57,8 @@
 #include "zend_operators.h"
 #include "zend_multiply.h"
 #include "zend_bitset.h"
+#include <signal.h>
 
-#ifdef HAVE_SIGNAL_H
-# include <signal.h>
-#endif
 #ifdef HAVE_UNISTD_H
 # include <unistd.h>
 #endif

Zend/zend_signal.c

@@ -30,10 +30,7 @@
 
 #include "zend.h"
 #include "zend_globals.h"
-
-#ifdef HAVE_SIGNAL_H
 #include <signal.h>
-#endif
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>

Zend/zend_signal.h

@@ -23,9 +23,7 @@
 
 #ifdef ZEND_SIGNALS
 
-# ifdef HAVE_SIGNAL_H
-#  include <signal.h>
-# endif
+#include <signal.h>
 
 #ifndef NSIG
 #define NSIG 65

ext/standard/exec.c

@@ -31,9 +31,8 @@
 #if HAVE_SYS_WAIT_H
 #include <sys/wait.h>
 #endif
-#if HAVE_SIGNAL_H
+
 #include <signal.h>
-#endif
 
 #if HAVE_SYS_TYPES_H
 #include <sys/types.h>

ext/standard/mail.c

@@ -35,10 +35,8 @@
 #endif
 
 #if PHP_SIGCHILD
-#if HAVE_SIGNAL_H
 #include <signal.h>
 #endif
-#endif
 
 #include "php_syslog.h"
 #include "php_mail.h"

ext/standard/proc_open.c

@@ -38,9 +38,7 @@
 #if HAVE_SYS_WAIT_H
 #include <sys/wait.h>
 #endif
-#if HAVE_SIGNAL_H
 #include <signal.h>
-#endif
 
 #if HAVE_SYS_STAT_H
 #include <sys/stat.h>

main/main.c

@@ -39,9 +39,9 @@
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
-#if HAVE_SIGNAL_H
+
 #include <signal.h>
-#endif
+
 #if HAVE_SETLOCALE
 #include <locale.h>
 #endif

sapi/cgi/cgi_main.c

@@ -45,9 +45,7 @@
 # include <unistd.h>
 #endif
 
-#if HAVE_SIGNAL_H
-# include <signal.h>
-#endif
+#include <signal.h>
 
 #if HAVE_SETLOCALE
 # include <locale.h>
@@ -1779,7 +1777,6 @@ int main(int argc, char *argv[])
 	char *decoded_query_string;
 	int skip_getopt = 0;
 
-#ifdef HAVE_SIGNAL_H
 #if defined(SIGPIPE) && defined(SIG_IGN)
 	signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE in standalone mode so
 								that sockets created via fsockopen()
@@ -1788,7 +1785,6 @@ int main(int argc, char *argv[])
 								does that for us!  [email protected]
 								20000419 */
 #endif
-#endif
 
 #ifdef ZTS
 	php_tsrm_startup();