commit 8dee88fe931e44f3b3708c488aaeecfaabafdcd5
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Dec 2 03:28:33 2022 +0100

    configure.ac: Add missing int return types to main (#7407)
    
    Implicit ints are a language feature that was removed in C99 and
    future compilers may require declaration of all return types.

--- a/configure.ac
+++ b/configure.ac
@@ -1039,7 +1039,7 @@ AC_CHECK_FUNCS(sem_init)
 if test "$ac_cv_func_sem_init" = "yes"; then
 AC_MSG_CHECKING(for working sem_init())
 AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <semaphore.h>
-	main () {
+	int main () {
 		sem_t s;
 		return sem_init(&s,0,0);
 		}
@@ -1072,7 +1072,7 @@ AC_SYS_LARGEFILE
 if test "$ac_cv_sys_file_offset_bits" = "no"; then
   AC_MSG_CHECKING(for native large file support)
   AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <unistd.h>
-    main () {
+    int main () {
     return !(sizeof(off_t) == 8);
   }]])],[ac_cv_sys_file_offset_bits=64; AC_DEFINE(_FILE_OFFSET_BITS,64)
    AC_MSG_RESULT(yes)],[AC_MSG_RESULT(no)],[])
@@ -1110,7 +1110,7 @@ dnl EKU: try to determine the alignment
 dnl      replaces FB_ALIGNMENT and FB_DOUBLE_ALIGN in src/jrd/common.h
 AC_MSG_CHECKING(alignment of long)
 AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <semaphore.h>
-main () {
+int main () {
   struct s {
     char a;
     union { long long x; sem_t y; } b;
@@ -1121,7 +1121,7 @@ AC_MSG_RESULT($ac_cv_c_alignment)
 AC_DEFINE_UNQUOTED(FB_ALIGNMENT, $ac_cv_c_alignment, [Alignment of long])
 
 AC_MSG_CHECKING(alignment of double)
-AC_RUN_IFELSE([AC_LANG_SOURCE([[main () {
+AC_RUN_IFELSE([AC_LANG_SOURCE([[int main () {
   struct s {
     char a;
     double b;