[cheese] Work around non-existent Makefile during clean

[David King <davidk src gnome org>]

commit 725bc89e15acce15231ce5a3d1fe6df863db345d
Author: David King <amigadave amigadave com>
Date:   Mon Mar 3 21:38:34 2014 +0000

    Work around non-existent Makefile during clean

 Makefile.am |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index acdbcde..c0bd8cd 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -458,7 +458,9 @@ all-local: $(bin_PROGRAMS)
 check-local: test
        cd $(gtkdoc_builddir) && $(MAKE) $(AM_MAKEFlAGS) check
 clean-local: lcov-clean
-       cd $(gtkdoc_builddir) && $(MAKE) $(AM_MAKEFLAGS) clean
+       cd $(gtkdoc_builddir) && if test -e Makefile ; then \
+               $(MAKE) $(AM_MAKEFLAGS) clean ; \
+       fi
        find . -name '*.gcno' -exec rm -f {} +
 distclean-local:
        cd $(gtkdoc_builddir) && $(MAKE) $(AM_MAKEFLAGS) distclean