libgcobol: Check for struct tm tm_zone

intrinsic.cc doesn't compile on Solaris:

/vol/gcc/src/hg/master/cobol/libgcobol/intrinsic.cc: In function ‘void
__gg__formatted_current_date(cblc_field_t*, cblc_field_t*, std::size_t,
std::size_t)’:
/vol/gcc/src/hg/master/cobol/libgcobol/intrinsic.cc:1480:6: error: ‘struct
std::tm’ has no member named ‘tm_zone’; did you mean ‘tm_mon’?
 1480 |   tm.tm_zone = "GMT";
      |      ^~~~~~~
      |      tm_mon

struct tm.tm_zone is new in POSIX.1-2024, thus cannot be assumed to be
present universally.

This patch checks for its presence and guards the use accordingly.

Bootstrapped without regressions on amd64-pc-solaris2.11,
sparcv9-sun-solaris2.11, and x86_64-pc-solaris2.11.

2025-04-08  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	libgcobol:
	* configure.ac: Check for struct tm.tm_zone.
	* configure, config.h.in: Regenerate.
	* intrinsic.cc (__gg__formatted_current_date): Guard tm.tm_zone
	use with HAVE_STRUCT_TM_TM_ZONE.

libgcobol/config.h.in

@@ -72,6 +72,9 @@
 /* Define to 1 if you have the `strtof128' function. */
 #undef HAVE_STRTOF128
 
+/* Define to 1 if `tm_zone' is a member of `struct tm'. */
+#undef HAVE_STRUCT_TM_TM_ZONE
+
 /* Define to 1 if you have the <sys/stat.h> header file. */
 #undef HAVE_SYS_STAT_H
 

libgcobol/configure

@@ -2449,6 +2449,63 @@ $as_echo "$ac_res" >&6; }
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
 } # ac_fn_cxx_check_func
+
+# ac_fn_cxx_check_member LINENO AGGR MEMBER VAR INCLUDES
+# ------------------------------------------------------
+# Tries to find if the field MEMBER exists in type AGGR, after including
+# INCLUDES, setting cache variable VAR accordingly.
+ac_fn_cxx_check_member ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2.$3" >&5
+$as_echo_n "checking for $2.$3... " >&6; }
+if eval \${$4+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$5
+int
+main ()
+{
+static $2 ac_aggr;
+if (ac_aggr.$3)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  eval "$4=yes"
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$5
+int
+main ()
+{
+static $2 ac_aggr;
+if (sizeof ac_aggr.$3)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  eval "$4=yes"
+else
+  eval "$4=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$$4
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_cxx_check_member
 cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
@@ -11693,7 +11750,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11696 "configure"
+#line 11753 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11799,7 +11856,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11802 "configure"
+#line 11859 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -17434,6 +17491,19 @@ $as_echo "#define USE_IEC_60559 1" >>confdefs.h
 
 
 
+# struct tm tm_zone is a POSIX.1-2024 addition.
+ac_fn_cxx_check_member "$LINENO" "struct tm" "tm_zone" "ac_cv_member_struct_tm_tm_zone" "#include <time.h>
+"
+if test "x$ac_cv_member_struct_tm_tm_zone" = xyes; then :
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STRUCT_TM_TM_ZONE 1
+_ACEOF
+
+
+fi
+
+
 if test "${multilib}" = "yes"; then
   multilib_arg="--enable-multilib"
 else

libgcobol/configure.ac

@@ -231,6 +231,9 @@ elif test "${ENABLE_LIBQUADMATH_SUPPORT}" = "default" ; then
 fi
 LIBGCOBOL_CHECK_FLOAT128
 
+# struct tm tm_zone is a POSIX.1-2024 addition.
+AC_CHECK_MEMBERS([struct tm.tm_zone],,,[#include <time.h>])
+
 if test "${multilib}" = "yes"; then
   multilib_arg="--enable-multilib"
 else

libgcobol/intrinsic.cc

@@ -1482,7 +1482,9 @@ __gg__formatted_current_date( cblc_field_t *dest, // Destination string
   __gg__clock_gettime(CLOCK_REALTIME, &ts);
 
   struct tm tm = {};
+#ifdef HAVE_STRUCT_TM_TM_ZONE
   tm.tm_zone = "GMT";
+#endif
   if( is_zulu )
     {
     gmtime_r(&ts.tv_sec, &tm);