diff --git a/build/libtool.m4 b/build/libtool.m4
index 8ee7b453010..5b518d50e4e 100644
--- a/build/libtool.m4
+++ b/build/libtool.m4
@@ -277,7 +277,7 @@ dnl This sometimes fails to find confdefs.h, for some reason.
 dnl [#]line __oline__ "[$]0"
 [#]line __oline__ "configure"
 #include "confdefs.h"
-int main() {
+int main(void) {
 ; return 0; }
 EOF
 if AC_TRY_EVAL(ac_link) && test -s conftest${ac_exeext}; then
@@ -978,8 +978,8 @@ else
 #  endif
 #endif
 
-void fnord() { int i=42;}
-int main ()
+void fnord(void) { int i=42;}
+int main (void)
 {
   void *self = dlopen (0, LT_DLGLOBAL|LT_DLLAZY_OR_NOW);
   int status = $lt_dlunknown;
@@ -2750,7 +2750,7 @@ _LT_AC_TAGVAR(objext, $1)=$objext
 lt_simple_compile_test_code="int some_variable = 0;"
 
 # Code to be used in simple link tests
-lt_simple_link_test_code='int main(){return(0);}'
+lt_simple_link_test_code='int main(void){return(0);}'
 
 _LT_AC_SYS_COMPILER
 
@@ -4640,7 +4640,7 @@ void nm_test_func(){}
 #ifdef __cplusplus
 }
 #endif
-int main(){nm_test_var='a';nm_test_func();return(0);}
+int main(void){nm_test_var='a';nm_test_func();return(0);}
 EOF
 
   if AC_TRY_EVAL(ac_compile); then
diff --git a/build/ltmain.sh b/build/ltmain.sh
index 2f1c8c9dc80..ff1685c8a89 100755
--- a/build/ltmain.sh
+++ b/build/ltmain.sh
@@ -3598,7 +3598,7 @@ EOF
 	  # whether they linked in statically or dynamically with ldd.
 	  $rm conftest.c
 	  cat > conftest.c <<EOF
-	  int main() { return 0; }
+	  int main(void) { return 0; }
 EOF
 	  $rm conftest
 	  if $LTCC $LTCFLAGS -o conftest conftest.c $deplibs; then
diff --git a/build/php.m4 b/build/php.m4
index 7fce1a085e6..74224698359 100644
--- a/build/php.m4
+++ b/build/php.m4
@@ -1210,27 +1210,27 @@ dnl PHP_MISSING_TIME_R_DECL
 dnl
 AC_DEFUN([PHP_MISSING_TIME_R_DECL],[
   AC_MSG_CHECKING([for missing declarations of reentrant functions])
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[struct tm *(*func)() = localtime_r]])],[
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[struct tm *(*func)(void) = localtime_r]])],[
     :
   ],[
     AC_DEFINE(MISSING_LOCALTIME_R_DECL,1,[Whether localtime_r is declared])
   ])
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[struct tm *(*func)() = gmtime_r]])],[
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[struct tm *(*func)(void) = gmtime_r]])],[
     :
   ],[
     AC_DEFINE(MISSING_GMTIME_R_DECL,1,[Whether gmtime_r is declared])
   ])
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[char *(*func)() = asctime_r]])],[
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[char *(*func)(void) = asctime_r]])],[
     :
   ],[
     AC_DEFINE(MISSING_ASCTIME_R_DECL,1,[Whether asctime_r is declared])
   ])
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[char *(*func)() = ctime_r]])],[
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[char *(*func)(void) = ctime_r]])],[
     :
   ],[
     AC_DEFINE(MISSING_CTIME_R_DECL,1,[Whether ctime_r is declared])
   ])
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <string.h>]], [[char *(*func)() = strtok_r]])],[
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <string.h>]], [[char *(*func)(void) = strtok_r]])],[
     :
   ],[
     AC_DEFINE(MISSING_STRTOK_R_DECL,1,[Whether strtok_r is declared])
@@ -1518,7 +1518,7 @@ AC_DEFUN([PHP_TEST_BUILD], [
   LIBS="$4 $LIBS"
   AC_LINK_IFELSE([AC_LANG_SOURCE([[
     $5
-    char $1();
+    char $1(void);
     int main(void) {
       $1();
       return 0;