Add basic support for the Blackfin architecture

For uClibc, the name of the Blackfin architecture is 'bfin'. Actually,
the naming of the architecture is quite messy: for toolchain tuples
and uClibc, it's bfin, but for the kernel, it's blackfin. We've
arbitraly choosen to name it "blackfin" in Crosstool-NG.

Add Blackfin-related uClibc patch to fix a build failure related to
fork() being used in unistd/daemon.c.

Yann E. MORIN:
Apply the patch to the kernel/linux build script to use 'linux'
in the noMMU tuples. See:
http://sourceware.org/ml/crossgcc/2010-04/msg00010.html

diff -durN gcc-4.4.0.orig/libgomp/configure gcc-4.4.0/libgomp/configure

--- gcc-4.4.0.orig/libgomp/configure	2009-04-21 11:08:08.000000000 +0200

+++ gcc-4.4.0/libgomp/configure	2009-05-27 21:38:19.000000000 +0200

@@ -3334,7 +3334,7 @@

 # Add -Wall -Werror if we are using GCC.

 if test "x$GCC" = "xyes"; then

-  XCFLAGS="$XCFLAGS -Wall -Werror"

+  XCFLAGS="$XCFLAGS -Wall"

 fi

 # Find other programs we need.