Makefile: Support passing environment variables through make--and use…

[daym]

… it to support host compilers that use environment variables CPATH etc. See Issue #609.

[tlaurion]

Hello @daym
I get the following on fedora-30:

make -C "/home/user/heads/build/busybox-1.28.0" CC=/home/user/heads/install/bin/musl-gcc -fdebug-prefix-map=/home/user/heads=heads -gno-record-gcc-switches -D__MUSL__  CPP=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-cpp CXXCPP=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-cpp CC_FOR_BUILD= BUILD_CC= HOSTCC= AR=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-ar LD=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-ld STRIP=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-strip NM=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-nm OBJCOPY=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-objcopy OBJDUMP=/home/user/heads/build/../crossgcc/x86_64-linux-musl/bin/x86_64-linux-musl-objdump PKG_CONFIG_PATH=/home/user/heads/install/lib/pkgconfig PKG_CONFIG_SYSROOT_DIR=/home/user/heads/install    
make[1]: Entering directory '/home/user/heads/build/busybox-1.28.0'
rm -f .kernelrelease
echo 1.28.0 > .kernelrelease
/home/user/heads/build/busybox-1.28.0/scripts/gen_build_files.sh /home/user/heads/build/busybox-1.28.0 /home/user/heads/build/busybox-1.28.0
make -f scripts/Makefile.build obj=scripts/basic
   -Wp,-MD,scripts/basic/.fixdep.d         -o scripts/basic/fixdep scripts/basic/fixdep.c  
/bin/sh: -Wp,-MD,scripts/basic/.fixdep.d: No such file or directory
make[2]: *** [scripts/Makefile.host:104: scripts/basic/fixdep] Error 127
make[1]: *** [Makefile:357: scripts_basic] Error 2
make[1]: Leaving directory '/home/user/heads/build/busybox-1.28.0'
make: *** [Makefile:384: /home/user/heads/build/busybox-1.28.0/.build] Error 1

make sure to:

cd heads
make BOARD=YourBoard real.clean
rm -rf crossgcc
make BOARD=YourBoard

And rebase on tope

[tlaurion]

@daym ping!

[tlaurion]

@osreserch: issue linked to this might expose roots of reproducibility issues?

[daym]

@daym ping!

I'd like to finish this, but I can't right now--because musl-cross in Guix doesn't work anymore.

I'm trying to update it now. The newest version of musl-cross errors out with the following (in gcc-5.3.0 in build2):

ctype_members.cc:50:17: error: cannot convert 'const short unsigned int*' to 'co
nst mask* {aka const unsigned int*}' in assignment
  this->_M_table = this->_M_c_locale_ctype->__ctype_b;

that's in ctype_byname::ctype_byname; commenting out now.

I needed this stuff to actually work for a client so I compiled heads without patches in RHEL for the time being.

I can only say that these environment variables are absolutely required in Guix (and are a GCC upstream feature)--and if you don't unset them in places where musl-cross is used (but have to keep them where host gcc is used), that's not going to end well.

[daym]

Rebased in new pull request #710.

[daym]

(I didn't fix the ctype issue in musl-cross - I just commented that part out because we don't use it anyway. Works fine)