Improve consistency between CC and CMake builds

[justsmth]

Description of changes:

The "CMake builder" now defers to the "CC builder" logic to determine which flags are appropriate for the compiler in the build environment. (Restores the usage of -ffile-prefix-map compiler option with CMake build, which had been disabled in a previous PR.)

Testing

Tested with GCC 7.2

❯ cc --version
cc (GCC) 7.2.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
...
❯ AWS_LC_SYS_CMAKE_BUILDER=1 cargo test -p aws-lc-sys --release
...
test result: ok. 95 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

     Running tests/sanity-tests.rs (target/release/deps/sanity_tests-84b2d0ab2e249e0a)

running 2 tests
test error_checking ... ok
test test_fips_mode ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

   Doc-tests aws_lc_sys

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
❯ AWS_LC_SYS_CMAKE_BUILDER=1 cargo test -p aws-lc-rs --release
...

test result: ok. 22 passed; 0 failed; 2 ignored; 0 measured; 0 filtered out; finished in 0.82s

Tested on MacOS (aarch64)

❯ AWS_LC_SYS_CMAKE_BUILDER=1 cargo test -p aws-lc-sys --release
...
test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

   Doc-tests aws_lc_sys

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
...
❯ strings target/release/build/aws-lc-sys-60dcdc2e10876109/out/build/artifacts/libaws_lc_0_21_2_crypto.a | grep justsmth || echo "nothing here"
nothing here

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.52%. Comparing base (c358484) to head (887ab74).
Report is 81 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #525      +/-   ##
==========================================
- Coverage   95.80%   92.52%   -3.28%     
==========================================
  Files          61       67       +6     
  Lines        8143     9277    +1134     
  Branches        0     9277    +9277     
==========================================
+ Hits         7801     8584     +783     
- Misses        342      422      +80     
- Partials        0      271     +271     

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[samuel40791765]

Is there a reason why we check this specific version?

[justsmth]

The -ffile-prefix-map option (which can strip build environment paths from the resulting binary) is only supported on GCC v8 and later. Our use of this flags was causing failures for projects building with CMake and an older GCC compiler.

This tests verifies that the path where the build is being performed (which is under the "runner"s home directory) is not found in the release binary.

[samuel40791765]

Ah that makes sense, I didn't realize this test dimension was intertwined with the flag. A comment here might help since the knowledge is a bit specific, but not absolutely required.

[samuel40791765]

Ah that makes sense, I didn't realize this test dimension was intertwined with the flag. A comment here might help since the knowledge is a bit specific, but not absolutely required.