PR modula2/115276 bugfix libgm2 wraptime.InitTM returns NIL

This patch fixes libgm2/libm2iso/wraptime.cc:InitTM so that
it does not always return NULL.  The incorrect autoconf macro
was used (inside InitTM) and the function short circuited
to return NULL.  The fix is to use HAVE_SYS_TIME_H and use
AC_HEADER_TIME in libgm2/configure.ac.

libgm2/ChangeLog:

	PR modula2/115276
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Use AC_HEADER_TIME.
	* libm2iso/wraptime.cc (InitTM): Check HAVE_SYS_TIME_H
	before using struct tm to obtain the size.

gcc/testsuite/ChangeLog:

	PR modula2/115276
	* gm2/isolib/run/pass/testinittm.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

gcc/testsuite/gm2/isolib/run/pass/testinittm.mod

@@ -0,0 +1,17 @@
+MODULE testinittm ;
+
+FROM wraptime IMPORT InitTM, tm ;
+FROM libc IMPORT printf, exit ;
+
+VAR
+   m: tm ;
+BEGIN
+   m := InitTM () ;
+   IF m = NIL
+   THEN
+      printf ("InitTM failed\n");
+      exit (1)
+   ELSE
+      printf ("InitTM passed\n")
+   END
+END testinittm.

libgm2/config.h.in

@@ -335,6 +335,9 @@
 /* Define to 1 if you have the ANSI C header files. */
 #undef STDC_HEADERS
 
+/* Define to 1 if you can safely include both <sys/time.h> and <time.h>. */
+#undef TIME_WITH_SYS_TIME
+
 /* Enable extensions on AIX 3, Interix.  */
 #ifndef _ALL_SOURCE
 # undef _ALL_SOURCE

libgm2/configure

@@ -6837,6 +6837,41 @@ $as_echo "#define HAVE_SYS_WAIT_H 1" >>confdefs.h
 
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether time.h and sys/time.h may both be included" >&5
+$as_echo_n "checking whether time.h and sys/time.h may both be included... " >&6; }
+if ${ac_cv_header_time+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+#include <sys/time.h>
+#include <time.h>
+
+int
+main ()
+{
+if ((struct tm *) 0)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_header_time=yes
+else
+  ac_cv_header_time=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_header_time" >&5
+$as_echo "$ac_cv_header_time" >&6; }
+if test $ac_cv_header_time = yes; then
+
+$as_echo "#define TIME_WITH_SYS_TIME 1" >>confdefs.h
+
+fi
+
 ac_fn_c_check_header_mongrel "$LINENO" "math.h" "ac_cv_header_math_h" "$ac_includes_default"
 if test "x$ac_cv_header_math_h" = xyes; then :
 
@@ -14544,7 +14579,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 14547 "configure"
+#line 14582 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -14650,7 +14685,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 14653 "configure"
+#line 14688 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H

libgm2/configure.ac

@@ -88,6 +88,7 @@ AC_ARG_WITH(cross-host,
 # Checks for header files.
 AC_HEADER_STDC
 AC_HEADER_SYS_WAIT
+AC_HEADER_TIME
 AC_CHECK_HEADER([math.h],
 	       [AC_DEFINE([HAVE_MATH_H], [1], [have math.h])])
 

libgm2/libm2iso/wraptime.cc

@@ -113,7 +113,7 @@ EXPORT(KillTimezone) (struct timezone *tv)
 
 /* InitTM - returns a newly created opaque type.  */
 
-#if defined(HAVE_STRUCT_TM) && defined(HAVE_MALLOC_H)
+#if defined(HAVE_SYS_TIME_H) && defined(HAVE_MALLOC_H)
 extern "C" struct tm *
 EXPORT(InitTM) (void)
 {