build-sys: Silence warning about missing AC_LANG_SOURCE call in acx_libwrap.m4

This updates the acx_libwrap.m4 macro for autoconf 2.68 and fixes
warnings like:
    configure.ac:471: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body

diff --git a/m4/acx_libwrap.m4 b/m4/acx_libwrap.m4
index e1602144b5995f46420bd16df9d56a0bcba49761..ccf8afc0aae83fe5c710b1dc6d67fdf5a9b43b2b 100644 (file)
--- a/m4/acx_libwrap.m4
+++ b/m4/acx_libwrap.m4
@@ -4,13 +4,13 @@ saved_LIBS="$LIBS"
 LIBS="$LIBS -lwrap"
 AC_MSG_CHECKING([for tcpwrap library and headers])
 AC_LINK_IFELSE(
-AC_LANG_PROGRAM(
+[AC_LANG_PROGRAM(
 [#include <tcpd.h>
 #include <syslog.h>
 int allow_severity = LOG_INFO;
 int deny_severity = LOG_WARNING;],
 [struct request_info *req;
-return hosts_access (req);]),
+return hosts_access (req);])],
 [AC_DEFINE(HAVE_LIBWRAP, [], [Have tcpwrap?])
 LIBWRAP_LIBS="-lwrap"
 AC_MSG_RESULT(yes)],