Allow user to enable internal GCC checking.
2013-01-16  Anton Kolesov <akolesov@synopsys.com>

    * build-elf32.sh, build-uclibc.sh: allow user to enable internal checking
    in GCC via ENABLE_CHECKING environment variable.
Merge branch 'arc_4_4-toolchain-dev' into arc-4.4-dev-only_uclibc_gcc_testing