GNUMakefile: don't fail if there is no .tarball-version

[Simon Josefsson]

'make dist' gets into a infloop in gnulib daily builds for me since
there is no .tarball-version file.  This should fix it.  Ok to push?

/Simon

2008-06-02  Simon Josefsson  <address@hidden>

        * top/GNUmakefile: Don't infloop if .tarball-version doesn't exist.

diff --git a/top/GNUmakefile b/top/GNUmakefile
index 0c1bc38..8c6b0b8 100644
--- a/top/GNUmakefile
+++ b/top/GNUmakefile
@@ -51,7 +51,8 @@ _autoreconf ?= autoreconf
 # Ensure that $(VERSION) is up to date for dist-related targets, but not
 # for others: rerunning autoreconf and recompiling everything isn't cheap.
 _have-git-version-gen := \
-  $(shell test -f $(srcdir)/$(_build-aux)/git-version-gen && echo yes)
+  $(shell test -f $(srcdir)/$(_build-aux)/git-version-gen && \
+       test -f $(srcdir)/.tarball-version && echo yes)
 ifeq ($(_have-git-version-gen)0,yes$(MAKELEVEL))
   _is-dist-target = $(filter-out %clean, \
     $(filter maintainer-% dist% alpha beta major,$(MAKECMDGOALS)))