Make RPM Provide: $varnishabi

We want VMODs to depend on the right ABI, so we need to provide
something they can depend on.  Do so, and hook that up with the RPM
build process.

redhat/Makefile.am

@@ -9,4 +9,5 @@ EXTRA_DIST =			\
 	varnish.spec		\
 	varnish.sysconfig	\
 	varnishlog.initrc	\
-	varnishncsa.initrc
+	varnishncsa.initrc	\
+	find-provides

redhat/find-provides

+#! /bin/sh
+
+# This script is used to inject the Varnish ABI into the provides.
+
+set -x
+
+if [ -x /usr/lib/rpm/find-requires ]; then
+    /usr/lib/rpm/find-requires "$@"
+fi
+
+cd $(dirname $0)/..
+
+printf '#include "vmod_abi.h"\nVMOD_ABI_Version' | cpp - -Iinclude | sed '/^#/D;s/"//g;s/\([A-Z]\)/\L\1/g;s/[^a-z0-9.]/-/g;s/varnish/varnishabi/'

redhat/varnish.spec

+%define    _use_internal_dependency_generator 0
+%define __find_provides %{_builddir}/varnish-%{version}%{?v_rc:-%{?v_rc}}/redhat/find-provides
 Summary: High-performance HTTP accelerator
 Name: varnish
 Version: 3.0.4