ld64: add tapi support to ld64-latest

[kencu]

this PR spins off the previous ld64-latest as ld64-274, which is the last version that will build without tapi support.

the ld64-latest port adds in tapi support using libtapi, but for the moment, at the same version as before (274).

this should allow ld64-latest to be updated now -- the latest version on the Apple open source website is 450.3, I notice, at this time.

[macportsbot]

Notifying maintainers:
@jeremyhu for port ld64.

[kencu]

ld64-latest (with tapi) builds and works on 10.13 against the MacOSX10.14.sdk, however, it does not function on 10.14, indicating a link error that looks unrelated to TAPI ; I think 274 is just too old for Mojave, so it would make sense to update ld64 to something more current before proceeding.

[kencu]

409.12 builds as well, with only a minor modification to the Makefile, but it requires another patch to libtapi for the newer functionality in ld64-409.12. It looks like this patch tpoechtrager/apple-libtapi@90d0bae might implement all the enhancements needed (to be further clarified), and would replace iain's libtapi zippered patch.

With tpoechtrager's patch for zippered support, ld64 @409.12 builds on 10.13 without issues.

[macportsbot]

Travis Build #10107 Failed.

Lint results

--->  Verifying Portfile for ld64
Warning: dyld-655.1.1.tar.gz - missing recommended checksum type: size
Warning: ld64-97-standalone-libunwind-headers.patch - missing recommended checksum type: size
Warning: ld64-97.17.tar.gz - missing recommended checksum type: size
Warning: ld64-127.2.tar.gz - missing recommended checksum type: size
Warning: ld64-236.3.tar.gz - missing recommended checksum type: size
Warning: ld64-274.2.tar.gz - missing recommended checksum type: size
--->  0 errors and 6 warnings found.

Port ld64-xcode success on xcode10.3. Log
Port ld64 success on xcode10.3. Log
Port ld64-97 fail on xcode10.3. Log
Port ld64-127 fail on xcode10.3. Log
Port ld64-236 fail on xcode10.3. Log
Port ld64-274 fail on xcode10.3. Log
Port ld64-latest fail on xcode10.3. Log
Port ld64-xcode success on xcode9.4. Log
Port ld64 success on xcode9.4. Log
Port ld64-97 fail on xcode9.4. Log
Port ld64-127 fail on xcode9.4. Log
Port ld64-236 success on xcode9.4. Log
Port ld64-274 success on xcode9.4. Log
Port ld64-latest success on xcode9.4. Log
Port ld64-latest fail on xcode8.3. Log
Port ld64's dependencies fail on xcode8.3. Log
Port ld64-97 fail on xcode8.3. Log
Port ld64-127 fail on xcode8.3. Log
Port ld64-236 fail on xcode8.3. Log
Port ld64-274 fail on xcode8.3. Log
Port ld64-xcode success on xcode8.3. Log
Port ld64-latest fail on xcode7.3. Log
Port ld64 fail on xcode7.3. Log
Port ld64-97 fail on xcode7.3. Log
Port ld64-127 fail on xcode7.3. Log
Port ld64-236 fail on xcode7.3. Log
Port ld64-274 fail on xcode7.3. Log

[kencu]

this has become a bit more complicated, now that just adding tapi to ld64-274 is not the only process here, and we're adding an upgrade to ld64-latest as well. I will reopen when this is ready for Jeremy (and any interested others) to review.