Add a makefile target to update the doc versions

This isn't automatic.
It does need to be invoked explicitly, after the package version is
 changed in configure.in, immediately before release, but that
 beats updating all of those files by hand for each release.

Patch contributed by Ron Lee.

svn path=/trunk/ogg/; revision=18941

doc/libogg/Makefile.am

@@ -24,3 +24,16 @@ dist_apidoc_DATA = bitpacking.html datastructures.html decoding.html encoding.ht
 	oggpack_writecopy.html oggpack_writeinit.html oggpack_writetrunc.html\
 	overview.html reference.html style.css
 
+update-doc-version:
+	@YEAR=$$(date +%Y); DAY=$$(date +%Y%m%d);					\
+	for f in $(srcdir)/*.html; do							\
+		sed -e "s/2000-[0-9]\{4\} Xiph.Org/2000-$$YEAR Xiph.Org/g"		\
+		    -e "s/libogg release [0-9. -]\+/libogg release $(VERSION) - $$DAY/g"\
+			< $$f > $$f.tmp;						\
+		if diff -q $$f $$f.tmp > /dev/null; then				\
+			rm $$f.tmp;							\
+		else									\
+			mv $$f.tmp $$f;							\
+		fi;									\
+	done;
+