--- acspecific-20081018.m4	2008-10-18 12:45:43.000000000 -0500
+++ acspecific.m4	2023-12-31 21:37:00.000000000 -0600
@@ -202,7 +202,7 @@
 [AC_MSG_CHECKING([whether the C compiler ($CC $CFLAGS $LDFLAGS) works])
 AC_LANG_SAVE
 AC_LANG_C
-AC_TRY_COMPILER([main(){return(0);}], ac_cv_prog_cc_works, ac_cv_prog_cc_cross)
+AC_TRY_COMPILER([int main(void){return(0);}], ac_cv_prog_cc_works, ac_cv_prog_cc_cross)
 AC_LANG_RESTORE
 AC_MSG_RESULT($ac_cv_prog_cc_works)
 if test $ac_cv_prog_cc_works = no; then
@@ -217,7 +217,7 @@
 [AC_MSG_CHECKING([whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) works])
 AC_LANG_SAVE
 AC_LANG_CPLUSPLUS
-AC_TRY_COMPILER([int main(){return(0);}], ac_cv_prog_cxx_works, ac_cv_prog_cxx_cross)
+AC_TRY_COMPILER([int main(void){return(0);}], ac_cv_prog_cxx_works, ac_cv_prog_cxx_cross)
 AC_LANG_RESTORE
 AC_MSG_RESULT($ac_cv_prog_cxx_works)
 if test $ac_cv_prog_cxx_works = no; then
@@ -820,7 +820,7 @@
 AC_CACHE_CHECK(whether closedir returns void, ac_cv_func_closedir_void,
 [AC_TRY_RUN([#include <sys/types.h>
 #include <$ac_header_dirent>
-int closedir(); main() { exit(closedir(opendir(".")) != 0); }],
+int closedir(); int main(void) { exit(closedir(opendir(".")) != 0); }],
   ac_cv_func_closedir_void=no, ac_cv_func_closedir_void=yes, ac_cv_func_closedir_void=yes)])
 if test $ac_cv_func_closedir_void = yes; then
   AC_DEFINE(VOID_CLOSEDIR)
@@ -911,7 +911,7 @@
 #define NGID 256
 #undef MAX
 #define MAX(x, y) ((x) > (y) ? (x) : (y))
-main()
+int main(void)
 {
   gid_t gidset[NGID];
   int i, n;
@@ -989,7 +989,7 @@
 AC_CACHE_CHECK(whether closedir returns void, ac_cv_func_closedir_void,
 [AC_TRY_RUN([#include <sys/types.h>
 #include <$ac_header_dirent>
-int closedir(); main() { exit(closedir(opendir(".")) != 0); }],
+int closedir(); int main(void) { exit(closedir(opendir(".")) != 0); }],
   ac_cv_func_closedir_void=no, ac_cv_func_closedir_void=yes, ac_cv_func_closedir_void=yes)])
 if test $ac_cv_func_closedir_void = yes; then
   AC_DEFINE(CLOSEDIR_VOID)
@@ -1001,7 +1001,7 @@
 # Some versions of Solaris or SCO have a broken fnmatch function.
 # So we run a test program.  If we are cross-compiling, take no chance.
 # Thanks to John Oleynick and Franc,ois Pinard for this test.
-[AC_TRY_RUN([main() { exit (fnmatch ("a*", "abc", 0) != 0); }],
+[AC_TRY_RUN([int main(void) { exit (fnmatch ("a*", "abc", 0) != 0); }],
 ac_cv_func_fnmatch_works=yes, ac_cv_func_fnmatch_works=no,
 ac_cv_func_fnmatch_works=no)])
 if test $ac_cv_func_fnmatch_works = yes; then
@@ -1087,7 +1087,7 @@
 #endif
 
 int
-main()
+main(void)
 {
 	char *data, *data2, *data3;
 	int i, pagesize;
@@ -1172,7 +1172,7 @@
 int     pg1, pg2, pg3, pg4;
 int     ng, np, s, child;
 
-main()
+int main(void)
 {
         pid = getpid();
         pg1 = getpgrp(0);
@@ -1228,7 +1228,7 @@
  * If this system has a BSD-style setpgrp, which takes arguments, exit
  * successfully.
  */
-main()
+int main(void)
 {
     if (setpgrp(1,1) == -1)
 	exit(0);
@@ -1291,7 +1291,7 @@
     }
   }
 }
-main() {
+int main(void) {
   pid_t parent = getpid ();
   pid_t child;
 
@@ -1360,7 +1360,7 @@
 #include <sys/resource.h>
 #include <stdio.h>
 /* HP-UX has wait3 but does not fill in rusage at all.  */
-main() {
+int main(void) {
   struct rusage r;
   int i;
   /* Use a field that we can force nonzero --
@@ -1582,7 +1582,7 @@
 # Sequent interprets utime(file, 0) to mean use start of epoch.  Wrong.
 AC_TRY_RUN([#include <sys/types.h>
 #include <sys/stat.h>
-main() {
+int main(void) {
 struct stat s, t;
 exit(!(stat ("conftestdata", &s) == 0 && utime("conftestdata", (long *)0) == 0
 && stat("conftestdata", &t) == 0 && t.st_mtime >= s.st_mtime
@@ -1647,7 +1647,7 @@
 AC_DEFUN(AC_FUNC_MEMCMP,
 [AC_CACHE_CHECK(for 8-bit clean memcmp, ac_cv_func_memcmp_clean,
 [AC_TRY_RUN([
-main()
+int main(void)
 {
   char c0 = 0x40, c1 = 0x80, c2 = 0x81;
   exit(memcmp(&c0, &c2, 1) < 0 && memcmp(&c1, &c2, 1) < 0 ? 0 : 1);
@@ -1805,7 +1805,7 @@
 #if !defined(__STDC__) || __STDC__ != 1
 #define volatile
 #endif
-main() {
+int main(void) {
   volatile char c = 255; exit(c < 0);
 }], ac_cv_c_char_unsigned=yes, ac_cv_c_char_unsigned=no)
 fi])
@@ -1819,7 +1819,7 @@
 [if test "$GCC" = yes; then
   ac_cv_c_long_double=yes
 else
-AC_TRY_RUN([int main() {
+AC_TRY_RUN([int main(void) {
 /* The Stardent Vistra knows sizeof(long double), but does not support it.  */
 long double foo = 0.0;
 /* On Ultrix 4.3 cc, long double is 4 and double is 8.  */
@@ -1834,7 +1834,7 @@
 AC_DEFUN(AC_INT_16_BITS,
 [AC_OBSOLETE([$0], [; instead use AC_CHECK_SIZEOF(int)])dnl
 AC_MSG_CHECKING(whether int is 16 bits)
-AC_TRY_RUN([main() { exit(sizeof(int) != 2); }],
+AC_TRY_RUN([int main(void) { exit(sizeof(int) != 2); }],
  [AC_MSG_RESULT(yes)
  AC_DEFINE(INT_16_BITS)], AC_MSG_RESULT(no))
 ])
@@ -1842,7 +1842,7 @@
 AC_DEFUN(AC_LONG_64_BITS,
 [AC_OBSOLETE([$0], [; instead use AC_CHECK_SIZEOF(long)])dnl
 AC_MSG_CHECKING(whether long int is 64 bits)
-AC_TRY_RUN([main() { exit(sizeof(long int) != 8); }],
+AC_TRY_RUN([int main(void) { exit(sizeof(long int) != 8); }],
  [AC_MSG_RESULT(yes)
  AC_DEFINE(LONG_64_BITS)], AC_MSG_RESULT(no))
 ])
