Makefile: Restructure for multilibs
Several Zephyr SDK toolchains support multilibs.
Instead of hard-coding locations of the libraries, the proper/cleanest way
is to query the GCC compiler for the locations of libgcc and libc.
However, in order to do this, we need to ensure a certain order of
initialization in the Makefile:
1. Determine CROSS_COMPILE.
We cannot determine LIB_INCLUDE_DIR, TOOLCHAIN_CFLAGS yet, as we don't
know the KBUILD_CFLAGS yet.
2. Calculate KBUILD_CFLAGS using CROSS_COMPILE
KBUILD_CFLAGS often need the compiler to validate options, i.e:
KBUILD_CFLAGS += $(call cc-option,-mabi=aapcs -mthumb -mcpu=cortex-m0)
However, LIB_INCLUDE_DIR, TOOLCHAIN_CFLAGS should not be needed for this
3. Finally, using CROSS_COMPILE and KBUILD_CFLAGS determine LIB_INCLUDE_DIR,
TOOLCHAIN_CFLAGS by querying GCC using -print-libgcc-file-name and
-print-multi-directory command line options.
This change should only affect Zephyr SDK toolchains, all other toolchains
are expected to function as before.
Change-Id: I27b460d46fe65d05fcb8bafb51cd6b3deba275ed
Signed-off-by: Juro Bystricky <juro.bystricky@intel.com>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
2 files changed
