diff --git a/contrib/subtree/Makefile b/contrib/subtree/Makefile
index 4030a168986d29bdbb2cd982a2e819ce009580f6..d888d4516114c719e46ab7f2aeb24e63618b7fac 100644
--- a/contrib/subtree/Makefile
+++ b/contrib/subtree/Makefile
@@ -3,17 +3,23 @@
 
 prefix ?= /usr/local
 mandir ?= $(prefix)/share/man
-libexecdir ?= $(prefix)/libexec/git-core
-gitdir ?= $(shell git --exec-path)
+gitexecdir ?= $(prefix)/libexec/git-core
 man1dir ?= $(mandir)/man1
 
-gitver ?= $(word 3,$(shell git --version))
+../../GIT-VERSION-FILE: FORCE
+	$(MAKE) -C ../../ GIT-VERSION-FILE
+
+-include ../../GIT-VERSION-FILE
 
 # this should be set to a 'standard' bsd-type install program
-INSTALL ?= install
+INSTALL  ?= install
+RM       ?= rm -f
+
+ASCIIDOC = asciidoc
+XMLTO    = xmlto
 
-ASCIIDOC_CONF      = ../../Documentation/asciidoc.conf
-MANPAGE_NORMAL_XSL =  ../../Documentation/manpage-normal.xsl
+ASCIIDOC_CONF = ../../Documentation/asciidoc.conf
+MANPAGE_XSL   = ../../Documentation/manpage-normal.xsl
 
 GIT_SUBTREE_SH := git-subtree.sh
 GIT_SUBTREE    := git-subtree
@@ -31,8 +37,8 @@ $(GIT_SUBTREE): $(GIT_SUBTREE_SH)
 doc: $(GIT_SUBTREE_DOC) $(GIT_SUBTREE_HTML)
 
 install: $(GIT_SUBTREE)
-	$(INSTALL) -d -m 755 $(DESTDIR)$(libexecdir)
-	$(INSTALL) -m 755 $(GIT_SUBTREE) $(DESTDIR)$(libexecdir)
+	$(INSTALL) -d -m 755 $(DESTDIR)$(gitexecdir)
+	$(INSTALL) -m 755 $(GIT_SUBTREE) $(DESTDIR)$(gitexecdir)
 
 install-doc: install-man
 
@@ -41,19 +47,21 @@ install-man: $(GIT_SUBTREE_DOC)
 	$(INSTALL) -m 644 $^ $(DESTDIR)$(man1dir)
 
 $(GIT_SUBTREE_DOC): $(GIT_SUBTREE_XML)
-	xmlto -m $(MANPAGE_NORMAL_XSL)  man $^
+	$(XMLTO) -m $(MANPAGE_XSL) man $^
 
 $(GIT_SUBTREE_XML): $(GIT_SUBTREE_TXT)
-	asciidoc -b docbook -d manpage -f $(ASCIIDOC_CONF) \
-		-agit_version=$(gitver) $^
+	$(ASCIIDOC) -b docbook -d manpage -f $(ASCIIDOC_CONF) \
+		-agit_version=$(GIT_VERSION) $^
 
 $(GIT_SUBTREE_HTML): $(GIT_SUBTREE_TXT)
-	asciidoc -b xhtml11 -d manpage -f $(ASCIIDOC_CONF) \
-		-agit_version=$(gitver) $^
+	$(ASCIIDOC) -b xhtml11 -d manpage -f $(ASCIIDOC_CONF) \
+		-agit_version=$(GIT_VERSION) $^
 
 test:
 	$(MAKE) -C t/ test
 
 clean:
-	rm -f *~ *.xml *.html *.1
-	rm -rf subproj mainline
+	$(RM) $(GIT_SUBTREE)
+	$(RM) *.xml *.html *.1
+
+.PHONY: FORCE
diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index db925ca76991c635ea53fe7f38d6608d08dfc4d5..fa1a5839af2d0c423adb51238fb330f555dc4dff 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -558,8 +558,9 @@ cmd_add_commit()
 		commit=$(add_squashed_msg "$rev" "$dir" |
 			 git commit-tree $tree $headp -p "$rev") || exit $?
 	else
+		revp=$(peel_committish "$rev") &&
 		commit=$(add_msg "$dir" "$headrev" "$rev" |
-			 git commit-tree $tree $headp -p "$rev") || exit $?
+			 git commit-tree $tree $headp -p "$revp") || exit $?
 	fi
 	git reset "$commit" || exit $?