[PATCH] build: don't clean __version__.py on 'make clean' in release tarballs

[Thomas De Schampheleire]

# HG changeset patch
# User J. Lewis Muir <jlmuir at anl.gov>
# Date 1409650124 -7200
#      Tue Sep 02 11:28:44 2014 +0200
# Node ID 0ac369b4cf23edb414a362df3a44d957a08ebd56
# Parent  90cf454edd709c616d1e5ea4f30fb4d02f0c01a4
build: don't clean __version__.py on 'make clean' in release tarballs

When running 'make clean' in an extracted release tarball, file
mercurial/__version__.py is removed, causing a subsequent install to
indicate 'version unknown'.

This problem was reported in the past [1] and a patch proposed in that mail,
but was never properly sent nor applied.

[1] http://selenic.com/pipermail/mercurial/2010-December/036249.html

diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -56,7 +56,8 @@
 	find contrib doc hgext i18n mercurial tests \
 		\( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';'
 	rm -f $(addprefix mercurial/,$(notdir $(wildcard mercurial/pure/[a-z]*.py)))
-	rm -f MANIFEST MANIFEST.in mercurial/__version__.py hgext/__index__.py tests/*.err
+	rm -f MANIFEST MANIFEST.in hgext/__index__.py tests/*.err
+	if test -d .hg; then rm -f mercurial/__version__.py; fi
 	rm -rf build mercurial/locale
 	$(MAKE) -C doc clean