build-sys: do not assume $(top_srcdir)/.version file always exists

The issue was visible when trying to perform 'make distcheck'
without the .version file.

Reported-by: Craig Small <csmall@enc.com.au>
Reference: http://www.freelists.org/post/procps/watch-8bit-and-make-distcheck
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/Makefile.am b/Makefile.am
index 45aad49b3d5414d64c99d2eeb4d78dcc039d1268..5d373e2651859220fc0ad386c06a0d5ab3408fa0 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -108,7 +108,9 @@ dist_procpsng_DATA = \
        Documentation/BUGS \
        Documentation/FAQ
 
-BUILT_SOURCES = $(top_srcdir)/.version
+@ if [ -f $(top_srcdir)/.version ]; then \
+  BUILT_SOURCES = $(top_srcdir)/.version \
+fi
 $(top_srcdir)/.version:
        echo $(VERSION) > $@-t && mv $@-t $@
 dist-hook: