Require ABI compatibility with VRT 6.0.

This requires a workaround for the problem in Varnish issue #2508.

Makefile.am

@@ -14,12 +14,10 @@ MAINTAINERCLEANFILES = $(dist_man_MANS)
 
 vmod_re.3: README.rst
 
-README.rst: src/vmod_re.man.rst
+README.rst: src/vmod_re.vcc
+	$(MAKE) -C src vmod_re.man.rst
 	cp src/vmod_re.man.rst README.rst
 
-src/vmod_re.man.rst:
-	make -C src vmod_re.man.rst
-
 %.1 %.2 %.3 %.4 %.5 %.6 %.7 %.8 %.9:
 if HAVE_RST2MAN
 	${RST2MAN} $< $@

src/Makefile.am

@@ -9,10 +9,13 @@ libvmod_re_la_SOURCES = \
 	vcc_if.h \
 	vmod_re.c
 
-vcc_if.c: vcc_if.h
+vcc_if.h vmod_re.rst vmod_re.man.rst: vcc_if.c
 
-vcc_if.h vmod_re.man.rst: @VMODTOOL@ $(top_srcdir)/src/vmod_re.vcc
-	@VMODTOOL@ $(top_srcdir)/src/vmod_re.vcc
+# The sed command fixes the bug concerning $ABI vrt that is addressed
+# by Varnish issue #2508.
+vcc_if.c: vmod_re.vcc
+	@VMODTOOL@ $(srcdir)/vmod_re.vcc
+	sed -i '/vrt_major/s/0/6/' vcc_if.c
 
 VMOD_TESTS = $(top_srcdir)/src/tests/*.vtc
 .PHONY: $(VMOD_TESTS)

src/vmod_re.vcc

@@ -10,6 +10,8 @@
 
 $Module re 3 Varnish Module for Regular Expression Matching with Subexpression Capture
 
+$ABI vrt
+
 DESCRIPTION
 ===========