diff --git a/builds/unix/configure.raw b/builds/unix/configure.raw
index 43a76568c..886d50b6f 100644
--- a/builds/unix/configure.raw
+++ b/builds/unix/configure.raw
@@ -50,7 +50,7 @@ if test ${cross_compiling} = yes; then
 
   AC_MSG_CHECKING([for suffix of native executables])
   rm -f a.* b.* a_out.exe conftest.*
-  echo > conftest.c "int main() { return 0;}"
+  echo > conftest.c "int main(void) { return 0;}"
   ${CC_BUILD} conftest.c || AC_MSG_ERROR([native C compiler is not working])
   rm -f conftest.c
   if test -x a.out -o -x b.out -o -x conftest; then
diff --git a/builds/unix/freetype2.m4 b/builds/unix/freetype2.m4
index 0cafc8e8c..51843f5fa 100644
--- a/builds/unix/freetype2.m4
+++ b/builds/unix/freetype2.m4
@@ -121,7 +121,7 @@ AC_DEFUN([AC_CHECK_FT2],
 #include <stdlib.h>
 
 int
-main()
+main(void)
 {
   FT_Library library;
   FT_Error  error;