strip when linking

[mattip]

we should strip the linux binaries before shipping. Issue gh-19 assumed that we do not override CFLAGS, but we do.

[mattip]

It seems to work, the size in MB of the manylinux builds decreased:

wheel	before	after
cp36-cp36m-manylinux1_x86_64	19.2	12.5
cp38-cp38-manylinux1_i686	17.0	10.6

Edit: this was wrong, the commit changed nothing.

[seiko2plus]

@mattip, using -strip-all will not only remove the debugging symbol table but also remove other important tables such as symtab, I suggest replacing it with -strip-debug instead. try to use nm command to verify it.

[mattip]

@seiko2plus Who would use the symtab table?

[seiko2plus]

@mattip, It will not harm if we left the default generated elf sections untouched. symtab doesn't take that much space, the issue in debug_* sections. symtab is useful with Valgrind and simple backtraces. also, it could be helpful to trace the inner loops of ufunc, for example checking the binary support of SIMD optimizations through nm command.

[mattip]

My check was wrong, the file sizes did not change. I must have looked while upload was still in progress. The CFLAGS set in env_vars.sh overrides any subsequent changes in the multibuild system, so these CFLAGS are the ones that are appended to the gcc command line in numpy/distutils. In dcceacd I added --strip-debug

[seiko2plus]

pass it to the linker flags only to not break clang build, LDFLAGS="-Wl,--strip-debug"

[mattip]

done in gh-85

[mattip]

Closing in favor of gh-86