cmake: parameterized flags to not include standard defines/files

Not all compiles/linkers support the GCC flags to not include standard
defines, include files and libraries. So make these parameters such
that the toolchain can define them when supported.

Also, according to documentation, -nostdlib does the same for both
-nostartfiles and -nodefaultlibs. So remove the redundant ones.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>