* platforms/linux.make (PLATFORM_CHANGE_SEPARATOR_CMD): Define to 'cat'.

* platforms/linux.make (PLATFORM_CHANGE_SEPARATOR_CMD): Define to 'cat'.
(PLATFORM_TWEAK_CORLIB_SOURCES): Remove.
(platform-check): Avoid bash-ism.
* library.make: Simplify uses of $(patsubst x,y,$(foo)) to $(foo:x=y).
(core_sourcefile): Rename back to ...
(sourcefile): ... this.  Remove creation of redundant intermediate file.
(response): Change test for optimization, now that
PLATFORM_CHANGE_SEPARATOR_CMD is unconditional.  Combine with
platform-exclude handling.
(library_CLEAN_FILES): New variable to specify clean:-able files
close to where they're defined.
(test_response, btest_response): Simplify.
* executable.make (response): Change test for optimization.
(executable_CLEAN_FILES): New define.

Maintainability improvements.  Sorry, I'm still in the scratch-an-itch
mode with the build stuff :-)

svn path=/trunk/mcs/; revision=29490