add hint about how to get a missing m4m/ directory

diff --git a/configure.ac b/configure.ac
index c5a0319..f6d9f9f 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -4,6 +4,21 @@ AC_CONFIG_SRCDIR([libexif/exif-data.h])
 AC_CONFIG_HEADERS([config.h])
 AM_INIT_AUTOMAKE([gnu 1.8 dist-bzip2])
 
+if test ! -d "$srcdir/m4m"; then
+AC_MSG_ERROR([
+You are missing the m4m/ directory in your top
+$PACKAGE_TARNAME source directory.
+
+You are probably using an ill-maintained CVS tree.
+Running
+
+    cd $srcdir
+    cvs co m4m
+
+and re-running autogen.sh might help.
+])
+fi
+
 GP_CHECK_SHELL_ENVIRONMENT
 GP_CONFIG_MSG([Build])
 GP_CONFIG_MSG([Source code location],[${srcdir}])