Fix [perl #114812] Configure not finding isblank().

Configure would not find isblank() when run with g++ because
the probe used exit() without including <stdlib.h>.  The simplest fix
is to have the probe use return instead.

diff --git a/Configure b/Configure
index 7fa1804..a1bc835 100755 (executable)
--- a/Configure
+++ b/Configure
@@ -15068,9 +15068,9 @@ $cat >isblank.c <<'EOCP'
 int main() {
        int c = ' ';
        if (isblank(c))
-               exit(0);
+               return 0 ;
        else
-               exit(1);
+               return 1 ;
 }
 EOCP
 if $cc $ccflags $ldflags -o isblank isblank.c $libs >/dev/null 2>&1 ; then