libgcc: make sure symlinks are created in a valid directory

libgcc: make sure symlinks are created in a valid directory

When adding extra symlinks, we have to make sure that the directory
that the links are created in is valid. Added a check for this.

This is an incremental addition to commit
97f2a81d6796ddaf7bbaab86c2ab9039673c732c

(From OE-Core rev: ea297e807f4f84c281e0f8c6c4470ee3f3fa949b)

Signed-off-by: Alexandru-Cezar Sardan <alexandru.sardan@freescale.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>