Fix -implcit-int in configure script

diff -urN a/configure b/configure
--- a/configure	2003-06-18 09:07:26.000000000 -0400
+++ b/configure	2025-10-10 19:57:21.484163969 -0400
@@ -908,7 +908,7 @@
 #line 909 "configure"
 #include "confdefs.h"
 
-main(){return(0);}
+int main(){return(0);}
 EOF
 if { (eval echo configure:914: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   ac_cv_prog_cc_works=yes