cc: add options to differentiate the need for pass-1 and pass-2

In some cases, building the core pass-1 is unneeded, as the C library
will not try to build anything when installing headers, or sill not
install anything at all.

This is for example the case for newlib, wihch does not require a core
pass-1 since it builds nothing and installs no header.

This should also be the case for newer glibc-es with newer gcc-es,
which no longer require a core pass-1, since the circular dependency
glibc <-> gcc (about TLS?) has been resolved.

Reported-by: Trevor Woerner <trevor.woerner@linaro.org>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

CT_LOCAL_TARBALLS_DIR="${HOME}/src"

CT_SAVE_TARBALLS=y

CT_LOG_EXTRA=y

CT_ARCH_FLOAT_SW=y

CT_ARCH_arm=y

CT_BINUTILS_V_2_19_1a=y

CT_CC_V_4_3_4=y

CT_CC_LANG_CXX=y

CT_LIBC_NEWLIB_V_1_17_0=y

CT_DEBUG_gdb=y

CT_GDB_V_6_8a=y

CT_GMP_V_4_3_2=y

CT_MPFR_V_2_4_2=y