Re: musl-cross-make / litecross improvements

[Rich Felker <dalias@libc.org>]

On Fri, May 06, 2016 at 08:43:58AM +1000, Patrick Oppenlander wrote:
> On 03/05/16 14:48, Rich Felker wrote:
> >Let me know if any major bugs/inconveniences remain that I should
> >prioritize fixing.
> 
> Hi Rich,
> 
> used this for the first time today (commit 4afd97a). Ran into a
> build failure using this config.mak:
> 
> TARGET = arm-linux-musleabi
> OUTPUT = /opt/cross
> GCC_CONFIG += --with-cpu=cortex-a8
> 
> I can send a full build log to your personal mail (~600KiB) if it helps.
> 
> libtool: compile: /home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./gcc/xgcc -B/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./gcc/
> -B/arm-linux-musleabi/bin/ -B/arm-linux-musleabi/lib/ -isystem
> /arm-linux-musleabi/include -isystem /arm-linux-musleabi/sys-include -L/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./ld --sysroot=/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_sysroot
> -DHAVE_CONFIG_H -I. -I../../../src_toolchain/boehm-gc -I./include -I/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/src_toolchain/boehm-gc/include
> -fexceptions -Iinclude -I././targ-include -I.//libc/include -g -O2
> -MT os_dep.lo -MD -MP -MF .deps/os_dep.Tpo -c
> .../../../src_toolchain/boehm-gc/os_dep.c  -fPIC -DPIC -o
> .libs/os_dep.o
> .../../../src_toolchain/boehm-gc/os_dep.c:20:30: fatal error:
> linux/version.h: No such file or directory
> compilation terminated.

It looks like there's a useless dependency on kernel headers in stuff
for the target libs. I suspect you might have omitted the recommended
--enable-languages=c,c++ and let it build all langs; IIRC boehm-gc is
not built at all for a c/c++ only build. Other langs are completely
untested and probably don't work, but it would be nice to find out why
and fix the ones that are practical to fix.

I should probably also add COMMON_CONFIG += --enable-languages=c,c++
_before_ config.mak inclusion so that, by default, you get the working
configuration. Having this before config.mak should make it so any
--enable-languages option you manually add with += takes precedence.

> Are you planning on supporting GCC 5.3? I may be able to contribute
> some patches.

I suspect the same patches for 5.2 apply just fine, but I haven't
taken the time to test yet. If you can confirm they work or tweak them
so they work I'd be happy to add 5.3 support. Other versions I'd like
to support are 4.7.4 (last C-only, also last before some sketchy
optimizations were added) and 6.1.0, but in order to add a version it
should have proper support (at least the main musl patch with dynamic
linker names, include paths, etc. fully ported) rather than just being
enough to compile.

Rich