utimens: Fix warning on Android

utimens: Fix warning on Android

[Bruno Haible]

Building a testdir on Android, I see these warnings:

../../gllib/utimens.c:420:16: warning: call to undeclared function 'futimesat'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
../../gllib/utimens.c:441:13: warning: call to undeclared function 'futimesat'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]

The cause is this API-level conditional declaration:

/usr/include/sys/time.h:int futimesat(int __dir_fd, const char* __path, const struct timeval __times[2]) __INTRODUCED_IN(26);

Once this is fixed, I see another warning:

../../gllib/utimens.c:441:13: warning: call to undeclared function 'futimes'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]

Again, the cause is an API-level conditional declaration:

/usr/include/sys/time.h:int futimes(int __fd, const struct timeval __times[2]) __INTRODUCED_IN(26);

This patch fixes the warnings.


2023-01-10  Bruno Haible  <bruno@clisp.org>

	utimens: Fix warning on Android.
	* m4/utimens.m4 (gl_UTIMENS): Test for futimesat and futimes using
	gl_CHECK_FUNCS_ANDROID instead of AC_CHECK_FUNCS_ONCE.

diff --git a/m4/utimens.m4 b/m4/utimens.m4
index ae35ef789b..c5d9b69e6f 100644
--- a/m4/utimens.m4
+++ b/m4/utimens.m4
@@ -3,7 +3,7 @@ dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-dnl serial 11
+dnl serial 12
 
 AC_DEFUN([gl_UTIMENS],
 [
@@ -11,7 +11,9 @@ AC_DEFUN([gl_UTIMENS],
   AC_REQUIRE([gl_FUNC_UTIMES])
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
-  AC_CHECK_FUNCS_ONCE([futimes futimesat futimens utimensat lutimes])
+  AC_CHECK_FUNCS_ONCE([futimens utimensat lutimes])
+  gl_CHECK_FUNCS_ANDROID([futimes], [[#include <sys/time.h>]])
+  gl_CHECK_FUNCS_ANDROID([futimesat], [[#include <sys/time.h>]])
 
   if test $ac_cv_func_futimens = no && test $ac_cv_func_futimesat = yes; then
     dnl FreeBSD 8.0-rc2 mishandles futimesat(fd,NULL,time).  It is not