Add buildroot support for binutils-2.22 and gcc-4.6.3; all buildroot tools are...

Add buildroot support for binutils-2.22 and gcc-4.6.3; all buildroot tools are not called abc-nuttx-elf instead of abc-elf

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5213 42af7a65-404d-4744-a932-0658087f49c3