[PATCH] mkmf.rb and create_makefile - important for rubygems

Hi,

The following patch explains the significance of the second argument to 
the create_makefile method. I believe this patch is crucial, because 
rubygems uses the target_prefix internally, which affects how rubygems 
creates and installs C extensions.

Submitted on the tracker at:

http://rubyforge.org/tracker/index.php?func=detail&aid=15536&group_id=426&atid=1700

Thanks,

Dan

C:\diff -u mkmf.orig mkmf.rb
--- mkmf.orig   Tue Aug 21 19:24:50 2007
+++ mkmf.rb     Sat Nov 10 14:20:28 2007
@@ -1150,6 +1150,37 @@
  # load the file within a Ruby program later, that directory structure will
  # have to be followed, e.g. "require 'test/foo'".
  #
+# The +srcprefix+ should be used when your source files are not in the same
+# directory as your build script. This will not only eliminate the need for
+# you to manually copy the source files into the same directory as your 
build
+# script, but it also sets the proper +target_prefix+ in the generated
+# Makefile.
+#
+# Setting the +target_prefix+ will, in turn, install the generated 
binary in
+# a directory under your Config::CONFIG['sitearchdir'] that mimics your 
local
+# filesystem when you run 'make install'.
+#
+# For example, given the following file tree:
+#
+#    ext/
+#       extconf.rb
+#       test/
+#          foo.c
+#
+# And given the following code:
+#
+#    create_makefile('test/foo', 'test')
+#
+# That will set the +target_prefix+ in the generated Makefile to 
'test'. That,
+# in turn, will create the following file tree when installed via the
+# 'make install' command:
+#
+#    /path/to/ruby/sitearchdir/test/foo.so
+#
+# It is recommended that you use this approach to generate your makefiles,
+# instead of copying files around manually, because some third party
+# libraries may depend on the +target_prefix+ being set properly.
+#
  def create_makefile(target, srcprefix = nil)
    $target = target
    libpath = $DEFLIBPATH|$LIBPATH