In Xcode 11, ld added a new flag called -platform_version that can be used instead of the old -<platform>_version_min flags.
The new flag allows Clang to pass the SDK version from the driver to the linker.
This patch adopts the new -platform_version flag in Clang, and starts using it by default,
unless a linker version < 520 is passed to the driver.
Differential Revision: https://reviews.llvm.org/D71579
The test additions in r329110 are Darwin-specific, as they rely
on a code path that is reachabled when driver is invoked without
-target. Instead of making the old test checks Darwin-specific too,
let's simply split it into two files to ensure that the old
checks are still platform-agnostic. Thanks Chandler for
suggesting this!
llvm-svn: 329141
Alex Lorenz