Some versions of sed don't support .\+, so use ..* instead.

Some versions of sed don't support .\+, so use ..* instead.
Reported by Christian Ebert for MacOS X.

--- a/doc/Makefile	Thu Oct 05 15:51:54 2006 +0200
+++ b/doc/Makefile	Thu Oct 05 20:03:38 2006 +0200
@@ -28,7 +28,7 @@
 
 install: man
 	for i in $(MAN) ; do \
-	  subdir=`echo $$i | sed -n 's/.\+\.\([0-9]\)$$/man\1/p'` ; \
+	  subdir=`echo $$i | sed -n 's/..*\.\([0-9]\)$$/man\1/p'` ; \
 	  mkdir -p $(MANDIR)/$$subdir ; \
 	  $(INSTALL) $$i $(MANDIR)/$$subdir ; \
 	done