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-0.4.orig/Makefile.in ltrace-0.4/Makefile.in

 --- ltrace-0.4.orig/Makefile.in	2008-10-26 15:34:21.000000000 +0100

 +++ ltrace-0.4/Makefile.in	2008-10-26 15:37:40.000000000 +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/      \