diff --git a/configure b/configure
index e904d48..7124384 100755
--- a/configure
+++ b/configure
@@ -1129,7 +1129,7 @@ cat > conftest.$ac_ext << EOF
 #line 1130 "configure"
 #include "confdefs.h"
 
-main(){return(0);}
+int main(){return(0);}
 EOF
 if { (eval echo configure:1135: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   ac_cv_prog_cc_works=yes
@@ -1458,8 +1458,8 @@ else
 #define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
 #define XOR(e, f) (((e) && !(f)) || (!(e) && (f)))
 int main () { int i; for (i = 0; i < 256; i++)
-if (XOR (islower (i), ISLOWER (i)) || toupper (i) != TOUPPER (i)) exit(2);
-exit (0); }
+if (XOR (islower (i), ISLOWER (i)) || toupper (i) != TOUPPER (i)) return 2;
+return 0; }
 
 EOF
 if { (eval echo configure:1466: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null