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 ltrace-0.5.1.orig/Makefile.in ltrace-0.5.1/Makefile.in

--- ltrace-0.5.1.orig/Makefile.in	2009-03-16 17:24:08.000000000 +0100

+++ ltrace-0.5.1/Makefile.in	2009-03-16 17:43:09.000000000 +0100

@@ -5,6 +5,7 @@

 OS		:= @HOST_OS@

 ARCH		:= $(shell echo "@HOST_ARCH@" |sed -e s/i.86/i386/      \

 						   -e s/sun4u/sparc64/  \

+						   -e s/alpha.*/alpha/  \

 						   -e s/arm.*/arm/      \

 						   -e s/sa110/arm/      \

 						   -e s/ppc64/ppc/      \