time_r.h: Remove gmtime_r() and localtime_r() wrappers.

It seems these were only ever used in librpbase/TextOut_text.cpp.
The UI frontends use functions specific to the UI framework in use.

libfmt's <fmt/chrono.h> header has its own fmt::gmtime() and
fmt::localtime() wrappers, which do basically the same thing as
time_r.h did: _r() if available, or _s() on Windows; and fall
back to the non-reentrant version as a last resort.

CMakeLists.txt: Remove the gmtime_r() and localtime_r() checks.

src/CMakeLists.txt

@@ -13,20 +13,10 @@ CHECK_INCLUDE_FILE("dirent.h" HAVE_DIRENT_H)
 # Windows Universal CRT has this; older versions of MSVCRT do not.
 CHECK_INCLUDE_FILE("sys/stat.h" HAVE_SYS_STAT_H)
 
-# Check for reentrant time functions.
+# Check for timegm() or equivalent function.
 # NOTE: May be _gmtime32_s() or _gmtime64_s() on MSVC 2005+.
 # The "inline" part will detect that.
 INCLUDE(CheckSymbolExistsOrInline)
-CHECK_SYMBOL_EXISTS_OR_INLINE(gmtime_r "time.h" "time_t tm; gmtime_r(&tm, NULL);" HAVE_GMTIME_R)
-IF(NOT HAVE_GMTIME_R)
-	CHECK_SYMBOL_EXISTS_OR_INLINE(gmtime_s "time.h" "time_t tm; gmtime_s(NULL, &tm);" HAVE_GMTIME_S)
-ENDIF(NOT HAVE_GMTIME_R)
-CHECK_SYMBOL_EXISTS_OR_INLINE(localtime_r "time.h" "time_t tm; localtime_r(&tm, NULL);" HAVE_LOCALTIME_R)
-IF(NOT HAVE_LOCALTIME_R)
-	CHECK_SYMBOL_EXISTS_OR_INLINE(localtime_s "time.h" "time_t tm; localtime_s(NULL, &tm);" HAVE_LOCALTIME_S)
-ENDIF(NOT HAVE_LOCALTIME_R)
-
-# Other time functions.
 CHECK_SYMBOL_EXISTS_OR_INLINE(timegm "time.h" "struct tm tm; time_t x = timegm(&tm);" HAVE_TIMEGM)
 IF(NOT HAVE_TIMEGM)
 	# NOTE: MSVCRT's _mkgmtime64() has a range of [1970/01/01, 3000/12/31].

src/config.libc.h.in

@@ -25,18 +25,6 @@
 
 /** Time functions **/
 
-/* Define to 1 if you have the `gmtime_r` function. */
-#cmakedefine HAVE_GMTIME_R 1
-
-/* Define to 1 if you have the `gmtime_s` function. */
-#cmakedefine HAVE_GMTIME_S 1
-
-/* Define to 1 if you have the `localtime_r' function. */
-#cmakedefine HAVE_LOCALTIME_R 1
-
-/* Define to 1 if you have the `localtime_s' function. */
-#cmakedefine HAVE_LOCALTIME_S 1
-
 /* Define to 1 if you have the `timegm' function. */
 #cmakedefine HAVE_TIMEGM 1
 

src/time_r.h

@@ -21,48 +21,6 @@
 #endif /* _WIN32 */
 #include <time.h>
 
-#ifndef HAVE_GMTIME_R
-#  ifdef gmtime_r
-     // Old MinGW-w64 (3.1.0, Ubuntu 14.04) has incompatible *_r() macros.
-#    undef gmtime_r
-#  endif
-static inline struct tm *gmtime_r(const time_t *timep, struct tm *result)
-{
-#ifdef HAVE_GMTIME_S
-	return (gmtime_s(result, timep) == 0 ? result : NULL);
-#else /* !HAVE_GMTIME_S */
-	// cppcheck-suppress gmtimeCalled
-	struct tm *tm = gmtime(timep);
-	if (tm && result) {
-		*result = *tm;
-		return result;
-	}
-	return NULL;
-#endif /* GMTIME_S */
-}
-#endif /* HAVE_GMTIME_R */
-
-#ifndef HAVE_LOCALTIME_R
-#  ifdef localtime_r
-     // Old MinGW-w64 (3.1.0, Ubuntu 14.04) has incompatible *_r() macros.
-#    undef localtime_r
-#  endif
-static inline struct tm *localtime_r(const time_t *timep, struct tm *result)
-{
-#ifdef HAVE_LOCALTIME_S
-	return (localtime_s(result, timep) == 0 ? result : NULL);
-#else /* !HAVE_LOCALTIME_S */
-	// cppcheck-suppress localtimeCalled
-	struct tm *tm = localtime(timep);
-	if (tm && result) {
-		*result = *tm;
-		return result;
-	}
-	return NULL;
-#endif /* HAVE_LOCALTIME_S */
-}
-#endif /* HAVE_LOCALTIME_R */
-
 /** timegm() **/
 
 /**