configure.ac, include/timehead.h: check also for mere declarations of…

… localtime_r() etc.

Signed-off-by: Jim Klimov <[email protected]>

configure.ac

@@ -938,8 +938,12 @@ AC_CHECK_FUNCS(strtof strtok_r fileno sigemptyset sigaction,
 dnl For these we have a fallback implementation via the other,
 dnl if at least one is available, so initial check is quiet.
 dnl This typically pops up in POSIX vs. Windows builds:
-AC_CHECK_FUNCS(localtime_r localtime_s gmtime_r gmtime_s timegm _mkgmtime,
-	[], [])
+dnl Reminder: the former checks for declarations in headers,
+dnl the latter checks if known libraries suffice for linker.
+dnl Might need AC_CHECK_LIBS as well to populate the list with
+dnl known variants?
+AC_CHECK_DECLS([localtime_r, localtime_s, gmtime_r, gmtime_s, timegm, _mkgmtime], [], [], [$CODE_TIMEINCL])
+AC_CHECK_FUNCS(localtime_r localtime_s gmtime_r gmtime_s timegm _mkgmtime, [], [])
 
 AC_MSG_CHECKING([for at least one gmtime implementation])
 AS_IF([test x"${ac_cv_func_gmtime_s}-${ac_cv_func_gmtime_r}" = "xno-no" && test x"${ac_cv_have_decl_gmtime_s}-${ac_cv_have_decl_gmtime_r}" = "xno-no"], [

include/timehead.h

@@ -44,8 +44,8 @@ extern "C" {
 char * strptime(const char *buf, const char *fmt, struct tm *tm);
 #endif
 
-#ifndef HAVE_LOCALTIME_R
-# ifdef HAVE_LOCALTIME_S
+#if !(defined HAVE_LOCALTIME_R && HAVE_LOCALTIME_R) && !(defined HAVE_DECL_LOCALTIME_R && HAVE_DECL_LOCALTIME_R)
+# if (defined HAVE_LOCALTIME_S && HAVE_LOCALTIME_S) || (defined HAVE_DECL_LOCALTIME_S && HAVE_DECL_LOCALTIME_S)
 /* A bit of a silly trick, but should help on MSYS2 builds it seems */
 #  define localtime_r(timer, buf) localtime_s(timer, buf)
 # else
@@ -59,8 +59,8 @@ static inline struct tm *localtime_r( const time_t *timer, struct tm *buf ) {
 # endif
 #endif
 
-#ifndef HAVE_GMTIME_R
-# ifdef HAVE_GMTIME_S
+#if !(defined HAVE_GMTIME_R && HAVE_GMTIME_R) && !(defined HAVE_DECL_GMTIME_R && HAVE_DECL_GMTIME_R)
+# if (defined HAVE_GMTIME_S && HAVE_GMTIME_S) || (defined HAVE_DECL_GMTIME_S && HAVE_DECL_GMTIME_S)
 #  define gmtime_r(timer, buf) gmtime_s(timer, buf)
 # else
 #  include <string.h> /* memcpy */
@@ -73,8 +73,8 @@ static inline struct tm *gmtime_r( const time_t *timer, struct tm *buf ) {
 # endif
 #endif
 
-#ifndef HAVE_TIMEGM
-# ifdef HAVE__MKGMTIME
+#if !(defined HAVE_TIMEGM && HAVE_TIMEGM) && !(defined HAVE_DECL_TIMEGM && HAVE_DECL_TIMEGM)
+# if (defined HAVE__MKGMTIME && HAVE__MKGMTIME) || (defined HAVE_DECL__MKGMTIME && HAVE_DECL__MKGMTIME)
 #  define timegm(tm) _mkgmtime(tm)
 # else
 #  ifdef WANT_TIMEGM_FALLBACK