[Iftop-users] Improve C99 compatibility of the configure script

[Florian Weimer]

This patch is needed to fix a C99 compatibility issue in the configure
script.  Future compilers are likely to reject implicit function
declarations by default, causing these configure checks to fail always.

Related to:

  <https://fedoraproject.org/wiki/Changes/PortingToModernC>
  <https://fedoraproject.org/wiki/Toolchain/PortingToModernC>

diff --git a/configure b/configure
index a0bb579d62bd6658..4ea776e4318a39e7 100755
--- a/configure
+++ b/configure
@@ -5079,9 +5079,9 @@ else
 int main() {
     $type dummy;
     FILE *f=fopen("conftestval", "w");
-    if (!f) exit(1);
+    if (!f) return 1;
     fprintf(f, "%d\n", sizeof($1));
-    exit(0);
+    return 0;
 }
 
 _ACEOF
diff --git a/configure.ac b/configure.ac
index 886a23a353c01856..e9ef7f57d002c54e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -111,9 +111,9 @@ for type in u_int8_t u_int16_t u_int32_t ; do
 int main() {
     $type dummy;
     FILE *f=fopen("conftestval", "w");
-    if (!f) exit(1);
+    if (!f) return 1;
     fprintf(f, "%d\n", sizeof($1));
-    exit(0);
+    return 0;
 }
     ])], [
         x=`cat conftestval`

Thanks,
Florian