Suricata

This seems to fix the problem:

diff --git a/configure.in b/configure.in
index 849545d..af68365 100644
--- a/configure.in
+++ b/configure.in
@@ -430,10 +430,8 @@ esac
 #prelude

     AC_ARG_ENABLE(prelude,
-            [  --enable-prelude  Enable Prelude support for alerts],
-            [ enable_prelude=yes ],
-            [ enable_prelude=no ])
-    if test "$enable_prelude" = "yes"; then
+            [  --enable-prelude  Enable Prelude support for alerts])
+    if test "x$enable_prelude" != "xno"; then
         CFLAGS="$CFLAGS -DPRELUDE" 
         AM_PATH_LIBPRELUDE(0.9.9, , AC_MSG_ERROR(Cannot find libprelude: Is libprelude-config in the path?), no)
         if test "x${LIBPRELUDE_CFLAGS}" != "x"; then

Don't know it's necessarily the 'right' way to fix it though. Also - the various other --enable/--disable options probably need checking, at least --disable-nfqueue seems to exhibit the same problem.

Thanks Pierre - I am aware that one workaround is not passing --disable-prelude.

The basic issue I had was that I was writing a gentoo ebuild for suricata, and as part of that you give it a list of acceptable configure options and it automatically handles setting them to enable/disable based on the 'use flags' configured for the underlying OS build. In that case if you tell the ebuild a flag exists it must have a value one way or another.

More generally - I think it is useful to have these args and not some automated logic. There are cases where you may not want to build in a feature even if the build OS supports it, perhaps you are planning on using the binary on many other systems, etc...