m4: fcntl31: Remove check for struct f_owner_ex

struct f_owner_ex support was added to glibc 2.11 released in 2009.
Other libc of course contain it as well (musl, uclibc-ng, bionic) and we
can safely assume it's widely supported.

The check m4/ltp-fcntl.m4 was unnecessarily complicated. Adding struct
into AC_CHECK_TYPES in configure.ac would be much faster than compile
with AC_COMPILE_IFELSE.

Link: https://lore.kernel.org/ltp/20250808110102.454689-4-pvorel@suse.cz/
Reviewed-by: Avinesh Kumar <akumar@suse.de>
Reviewed-by: Li Wang <liwang@redhat.com>
Signed-off-by: Petr Vorel <pvorel@suse.cz>

Author: pevik

configure.ac

@@ -397,7 +397,6 @@ LTP_CHECK_LIBMNL
 LTP_CHECK_SELINUX
 LTP_CHECK_SYNC_ADD_AND_FETCH
 LTP_CHECK_SYSCALL_EVENTFD
-LTP_CHECK_SYSCALL_FCNTL
 LTP_CHECK_FSVERITY
 
 AX_CHECK_COMPILE_FLAG([-no-pie], [LTP_CFLAGS_NOPIE=1])

m4/ltp-fcntl.m4

@@ -44,13 +44,11 @@ static void cleanup(void);
 static void setown_pid_test(void);
 static void setown_pgrp_test(void);
 
-#if defined(HAVE_STRUCT_F_OWNER_EX)
 static void setownex_tid_test(void);
 static void setownex_pid_test(void);
 static void setownex_pgrp_test(void);
 
 static struct f_owner_ex orig_own_ex;
-#endif
 
 static void signal_parent(void);
 static void check_io_signal(char *des);
@@ -68,9 +66,7 @@ static int pipe_fds[2];
 
 static void (*testfunc[])(void) = {
 	setown_pid_test, setown_pgrp_test,
-#if defined(HAVE_STRUCT_F_OWNER_EX)
 	setownex_tid_test, setownex_pid_test, setownex_pgrp_test
-#endif
 };
 
 char *TCID = "fcntl31";
@@ -122,14 +118,12 @@ static void setup(void)
 	if (pgrp_pid < 0)
 		tst_brkm(TBROK | TERRNO, cleanup, "getpgid() failed");
 
-#if defined(HAVE_STRUCT_F_OWNER_EX)
 	/* get original f_owner_ex info */
 	TEST(fcntl(test_fd, F_GETOWN_EX, &orig_own_ex));
 	if (TEST_RETURN < 0) {
 		tst_brkm(TFAIL | TTERRNO, cleanup,
 			 "fcntl get original f_owner_ex info failed");
 	}
-#endif
 
 	/* get original pid info */
 	TEST(fcntl(test_fd, F_GETOWN));
@@ -183,7 +177,6 @@ static void setown_pgrp_test(void)
 	}
 }
 
-#if defined(HAVE_STRUCT_F_OWNER_EX)
 static void setownex_cleanup(void)
 {
 	TEST(fcntl(test_fd, F_SETOWN_EX, &orig_own_ex));
@@ -245,7 +238,6 @@ static void setownex_pgrp_test(void)
 
 	setownex_cleanup();
 }
-#endif
 
 static void test_set_and_get_sig(int sig, char *des)
 {