python/python3: use cc_basename to replace CC for checking compiler

python/python3: use cc_basename to replace CC for checking compiler

When working path contains "clang"/"gcc"/"icc", it might be part of $CC
because of the "--sysroot" parameter. That could cause judgement error
about clang/gcc/icc compilers.

eg: if build under /yocto/builds/xicc/,  bitbake python,  $CC will contains
xicc, will make $CC match *icc, but actuall xicc just folder name.

When "*icc" is matched, below errors are reported when
compiling python/python3:
x86_64-wrs-linux-gcc: error: strict: No such file or directory
x86_64-wrs-linux-gcc: error: unrecognized command line option '-fp-model'

Here use cc_basename to replace CC for checking compiler to avoid such
kind of issue.

Signed-off-by: Li Zhou <li.zhou@windriver.com>
Signed-off-by: Changqing Li <changqing.li@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>