Make tests pass on Alpine Linux

[davidlattimore]

I added a dockerfile to make it easier for those of us that don't run Alpine natively to have a look. In that image, I see the following tests fail:

• integration_test::program_name_02___trivial_main_c__
  • Insufficient .gnu.version allocation - For some reason we're attempting to write more data to .gnu.version than we allocated during the layout phase.
• integration_test::program_name_11___ifunc_c__
  • Ifuncs aren't supported on musl. I guess we need some way to skip this test for musl.
• integration_test::program_name_32___ifunc2_c__
  • Same as above
• integration_test::program_name_26___libc_integration_c__
  • Ifuncs again. Probably don't want to skip the whole test, but just the part of this test that's related to ifuncs.
• integration_test::program_name_27___rust_integration_rs__
  • Initially failed because I forgot to add clang to the installs in the dockerfile.
  • After that, this is failing because we're trying to run bash. Need to either switch to sh or maybe install bash in the image.

The following 3 tests also failed for me, but I didn't look at them, since I figured they'd be more of the same.

• integration_test::program_name_28___rust_integration_dynamic_rs__
• integration_test::program_name_29___cpp_integration_cc__
• integration_test::program_name_30___rust_tls_rs__

I probably won't get a chance to look more at any of this for a while, since I'm focusing my time on the linker-diff rewrite. If anyone would like to have a go at fixing any of these and needs more guidance, I'm definitely happy to help where I can.

Originally posted by @davidlattimore in #230 (comment)