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_EXPERIMENTAL=y

CT_LOCAL_TARBALLS_DIR="${HOME}/src"

CT_SAVE_TARBALLS=y

CT_ARCH_CPU="e300c3"

CT_ARCH_TUNE="e300c3"

CT_ARCH_powerpc=y

CT_TARGET_VENDOR="e300c3"

CT_KERNEL_linux=y

CT_KERNEL_V_2_6_36=y

CT_BINUTILS_V_2_21_1a=y

CT_BINUTILS_FOR_TARGET=y

CT_CC_V_4_5_2=y

CT_CC_LANG_CXX=y

CT_CC_EXTRA_CONFIG_ARRAY="--with-long-double-128"

# CT_CC_GCC_ENABLE_TARGET_OPTSPACE is not set

# CT_CC_GCC_SJLJ_EXCEPTIONS is not set

CT_LIBC_EGLIBC_V_2_12=y

# CT_LIBC_GLIBC_FORCE_UNWIND is not set

CT_LIBC_GLIBC_USE_PORTS=y

CT_GMP_V_5_0_1=y

CT_MPFR_V_3_0_0=y

CT_CLOOG_V_0_15_10=y

CT_MPC_V_0_8_2=y