Index: FindRuby.cmake
===================================================================
RCS file: /cvsroot/CMake/CMake/Modules/FindRuby.cmake,v
retrieving revision 1.7
diff -u -r1.7 FindRuby.cmake
--- FindRuby.cmake	7 Dec 2006 22:37:56 -0000	1.7
+++ FindRuby.cmake	18 Aug 2007 08:42:40 -0000
@@ -23,21 +23,20 @@
 
 FIND_PROGRAM(RUBY_EXECUTABLE NAMES ruby ruby1.8 ruby18 )
 
-EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "puts Config::CONFIG['archdir']"
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['archdir']"
    OUTPUT_VARIABLE RUBY_ARCH_DIR)
 
-
-EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "puts Config::CONFIG['libdir']"
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['libdir']"
    OUTPUT_VARIABLE RUBY_POSSIBLE_LIB_PATH)
 
-EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "puts Config::CONFIG['rubylibdir']"
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['rubylibdir']"
    OUTPUT_VARIABLE RUBY_RUBY_LIB_PATH)
 
-# remove the new lines from the output by replacing them with empty strings
-STRING(REPLACE "\n" "" RUBY_ARCH_DIR "${RUBY_ARCH_DIR}")
-STRING(REPLACE "\n" "" RUBY_POSSIBLE_LIB_PATH "${RUBY_POSSIBLE_LIB_PATH}")
-STRING(REPLACE "\n" "" RUBY_RUBY_LIB_PATH "${RUBY_RUBY_LIB_PATH}")
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['vendorlibdir']"
+   OUTPUT_VARIABLE RUBY_VENDOR_LIB_PATH)
 
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['vendorarchdir']"
+   OUTPUT_VARIABLE RUBY_VENDOR_ARCH_DIR)
 
 FIND_PATH(RUBY_INCLUDE_PATH
    NAMES ruby.h

This is another approach to this bug.
It adds 2 new variables which i propose to use from now on. And it adds a new option to the finder.

The 2 new variables are RUBY_EXTENSION_ARCH_DIR and RUBY_EXTENSION_LIB_DIR.
I added those to have an abstraction for the potential target paths. By
default those will point to the site_ruby paths.
(RUBY_SITEARCH_DIR and RUBY_SITELIB_DIR).

site_ruby should be the default path for ruby extensions. RUBY_ARCH_DIR
and RUBY_RUBY_LIB_PATH are usually reserved for the ruby stdlib.  There is a
patch around that adds a new subdir for extensions called vendor_ruby. That
gives distributors/packagers a namespace so they dont collide with user
installed extensions. So i added a new option called WANT_VENDOR_RUBY. I am
not sure whether it should be prefixed with RUBY_ or if the current name is
ok.  If this option is set the 2 new variables will use vendor_ruby instead.

Additionally the patch exports 2 new variables RUBY_VENDORARCH_DIR and
RUBY_VENDORLIB_DIR to be consistent with the site_ruby paths.

In the longterm i would really obsoletes all the RUBY_*ARCH_DIR AND
RUBY_*LIB_DIR variables and only export RUBY_EXTENSION_*DIR from the finder.

comments/critics?

Index: Modules/FindRuby.cmake
===================================================================
--- Modules/FindRuby.cmake.orig	2007-07-16 23:12:30.000000000 +0200
+++ Modules/FindRuby.cmake	2007-08-21 23:15:35.760662574 +0200
@@ -21,22 +21,65 @@ endif (RUBY_LIBRARY AND RUBY_INCLUDE_PAT
 #   RUBY_LIBDIR=`$RUBY -r rbconfig -e 'printf("%s",Config::CONFIG@<:@"libdir"@:>@)'`
 #   RUBY_LIBRUBYARG=`$RUBY -r rbconfig -e 'printf("%s",Config::CONFIG@<:@"LIBRUBYARG_SHARED"@:>@)'`
 
-FIND_PROGRAM(RUBY_EXECUTABLE NAMES ruby ruby1.8 ruby18 )
-
-EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "puts Config::CONFIG['archdir']"
-   OUTPUT_VARIABLE RUBY_ARCH_DIR)
+OPTION(WANT_VENDOR_RUBY "Use vendor_ruby if the ruby installation supports it. Will fall back to site_ruby. [default: off]")
 
+FIND_PROGRAM(RUBY_EXECUTABLE NAMES ruby ruby1.8 ruby18 )
 
-EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "puts Config::CONFIG['libdir']"
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['libdir']"
    OUTPUT_VARIABLE RUBY_POSSIBLE_LIB_PATH)
 
-EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "puts Config::CONFIG['rubylibdir']"
-   OUTPUT_VARIABLE RUBY_RUBY_LIB_PATH)
+#
+# Those are the paths of the ruby stdlib and should not be used.
+# I think those should be deprecated and any access to those should issue an warning.
+# How?
+#
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['archdir']"
+  OUTPUT_VARIABLE RUBY_ARCH_DIR)
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['rubylibdir']"
+  OUTPUT_VARIABLE RUBY_RUBY_LIB_PATH)
+
+#
+# site_ruby
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['sitearchdir']"
+   OUTPUT_VARIABLE RUBY_SITEARCH_DIR)
+
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['sitelibdir']"
+   OUTPUT_VARIABLE RUBY_SITELIB_DIR)
+#
+# vendor_ruby
+EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r vendor-specific -e "print 'true'"
+   OUTPUT_VARIABLE RUBY_HAS_VENDOR_RUBY)
+
+IF(RUBY_HAS_VENDOR_RUBY)
+    EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['vendorarchdir']"
+       OUTPUT_VARIABLE RUBY_VENDORARCH_DIR)
+
+    EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['vendorlibdir']"
+       OUTPUT_VARIABLE RUBY_VENDORLIB_DIR)
+ENDIF(RUBY_HAS_VENDOR_RUBY)
+
+#
+# Introducing 2 new variables which should be used in place of the variables above.
+# RUBY_EXTENSION_ARCH_DIR and RUBY_EXTENSION_LIB_DIR will by default point to site_ruby.
+# if WANT_VENDOR_RUBY is passed and the local ruby installation supports it
+#
+SET(RUBY_EXTENSION_ARCH_DIR RUBY_SITEARCH_DIR)
+SET(RUBY_EXTENSION_LIB_DIR  RUBY_SITELIB_DIR)
+
+IF(WANT_VENDOR_RUBY)
+   IF(RUBY_HAS_VENDOR_RUBY)
+      SET(RUBY_EXTENSION_ARCH_DIR RUBY_VENDORARCH_DIR)
+      SET(RUBY_EXTENSION_LIB_DIR  RUBY_VENDORLIB_DIR)
+   ELSE(RUBY_HAS_VENDOR_RUBY)
+      MESSAGE("vendor_ruby was requested but the ruby doesnt support it. Will fall back to site_ruby")
+   ENDIF(RUBY_HAS_VENDOR_RUBY)
+ENDIF(WANT_VENDOR_RUBY)
 
+# this is not needed if you use "print" inside the ruby statements
 # remove the new lines from the output by replacing them with empty strings
-STRING(REPLACE "\n" "" RUBY_ARCH_DIR "${RUBY_ARCH_DIR}")
-STRING(REPLACE "\n" "" RUBY_POSSIBLE_LIB_PATH "${RUBY_POSSIBLE_LIB_PATH}")
-STRING(REPLACE "\n" "" RUBY_RUBY_LIB_PATH "${RUBY_RUBY_LIB_PATH}")
+#STRING(REPLACE "\n" "" RUBY_ARCH_DIR "${RUBY_ARCH_DIR}")
+#STRING(REPLACE "\n" "" RUBY_POSSIBLE_LIB_PATH "${RUBY_POSSIBLE_LIB_PATH}")
+#STRING(REPLACE "\n" "" RUBY_RUBY_LIB_PATH "${RUBY_RUBY_LIB_PATH}")
 
 
 FIND_PATH(RUBY_INCLUDE_PATH
@@ -54,4 +97,6 @@ MARK_AS_ADVANCED(
   RUBY_EXECUTABLE
   RUBY_LIBRARY
   RUBY_INCLUDE_PATH
+  RUBY_ARCH_DIR
+  RUBY_RUBY_LIB_PATH
   )