configure: add return() statements in 3 AC_LANG_PROGRAM() blocks

This allows the dns and df plugins to get built also in the case the
configure script is run with `CC="gcc -Wall -Werror"`.

diff --git a/configure.in b/configure.in
index 877ac44..634727d 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1161,6 +1161,7 @@ FILE *fh;
 struct mntent *me;
 fh = setmntent ("/etc/mtab", "r");
 me = getmntent (fh);
+return(me->mnt_passno);
 ]]]
                        )],
                        [c_cv_have_one_getmntent="yes"],
@@ -1180,6 +1181,7 @@ me = getmntent (fh);
                                 int status;
                                 fh = fopen ("/etc/mnttab", "r");
                                 status = getmntent (fh, &mt);
+                                return(status);
 ]]]
                        )],
                        [c_cv_have_two_getmntent="yes"],
@@ -3042,6 +3044,7 @@ then
 ]]],
 [[[
   int val = PCAP_ERROR_IFACE_NOT_UP;
+  return(val);
 ]]]
                       )],
                       [c_cv_libpcap_have_pcap_error_iface_not_up="yes"],