[gnome-globalmenu] Sanity check for installations of previous version.

[Yu Feng <fengy src gnome org>]

commit 7b9106a967a7f1d9759992b2645c03f944df3b74
Author: Yu Feng <rainwoodman gmail com>
Date:   Mon Nov 9 23:01:18 2009 -0500

    Sanity check for installations of previous version.
    
    Relating to Issue 539

 Makefile.am     |    1 +
 Makefile.sanity |    9 +++++++++
 2 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 6aea15a..024e21c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -45,3 +45,4 @@ include $(top_srcdir)/Makefile.config
 doc_DATA = README COPYING ChangeLog AUTHORS INSTALL \
 	README.XFCE README.GNOME README.LEGACY
 
+include $(top_srcdir)/Makefile.sanity
diff --git a/Makefile.sanity b/Makefile.sanity
new file mode 100644
index 0000000..2551e80
--- /dev/null
+++ b/Makefile.sanity
@@ -0,0 +1,9 @@
+# check if the installation will conflict with installations of previous versions
+install-exec-hook:
+	@if [ -f $(DESTDIR)$(GTK_MODULES_DIR)/libglobalmenu-gnome.so ]; then \
+	echo "ERROR: $(DESTDIR)$(GTK_MODULES_DIR)/libglobalmenu-gnome.so is found"; \
+	echo "ERROR: this file is a leftover of an installation of a previous version"; \
+	echo "ERROR: Please remove the previous version, or at least this file."; \
+	echo "ERROR: otherwise your Global Menu will not work properly"; \
+	exit 1; \
+	fi;