[PATCH] make sure version numbers can be determined

Hi,

Someone reported me an installation problem, while installing MacRuby.

After a long investigation, it turned out to be because the reporter
was using a customized GREP_OPTIONS environment variable, set to the
"--color=always" value.

With that value, configure cannot determine MAJOR, MINOR and TEENY
because the output of `grep RUBY_VERSION version.h' is different
(probably because it contains ANSI sequences).

But configure doesn't complain about that, and leave you with
incomplete installation paths. I think configure should fail if one of
these numbers could not be determined. Following is an attempt to do
that, but I'm not an autotools expert, maybe there is a better way to
do it.

Laurent

Index: configure.in
===================================================================
--- configure.in	(revision 87)
+++ configure.in	(working copy)
@@ -67,6 +67,15 @@
 MAJOR=`expr "$rb_version" : '#define RUBY_VERSION
"\([0-9][0-9]*\)\.[0-9][0-9]*\.[0-9][0-9]*"'`
 MINOR=`expr "$rb_version" : '#define RUBY_VERSION
"[0-9][0-9]*\.\([0-9][0-9]*\)\.[0-9][0-9]*"'`
 TEENY=`expr "$rb_version" : '#define RUBY_VERSION
"[0-9][0-9]*\.[0-9][0-9]*\.\([0-9][0-9]*\)"'`
+if test "$MAJOR" = ""; then
+  AC_MSG_ERROR(could not determine MAJOR number from version.h)
+fi
+if test "$MINOR" = ""; then
+  AC_MSG_ERROR(could not determine MINOR number from version.h)
+fi
+if test "$TEENY" = ""; then
+  AC_MSG_ERROR(could not determine TEENY number from version.h)
+fi
 AC_SUBST(MAJOR)
 AC_SUBST(MINOR)
 AC_SUBST(TEENY)