Makefile: add target `update-peg'

Makefile

@@ -39,6 +39,7 @@ VCS = git
 GITHUB = git://github.com
 # also, if hggit extension is available:
 # VCS = hg
+VCS-PULLFLAGS = 
 
 
 #
@@ -56,6 +57,11 @@ $(LEG):
 peg:
 	$(VCS) clone $(GITHUB)/knieriem/peg
 
+update-peg:
+	cd peg && $(VCS) pull $(VCS-PULLFLAGS)
+	cd peg/leg && make clean
+
+
 #
 # access to original C source files
 #

README.markdown

@@ -46,6 +46,10 @@ finish the installation:
 
 See doc.go for an example how to use the package.
 
+To update [knieriem/peg][] run `gomake update-peg`. This
+will fetch available revisions from github, and remove the
+old *leg* binary.
+
 To create the command line program *markdown,* run
 
 	cd $GOROOT/src/pkg/github.com/knieriem/markdown