As discussed here:
https://github.com/llvm/llvm-project/pull/74394#issuecomment-2035264683
An unintentional change of behavior was introduced in #74394
This code introduced in #74394 :
The first time through
* SANITIZER_MIN_OSX_VERSION is not set
* parse -mmacosx-version-min and set MACOSX_VERSION_MIN_FLAG
* Set and cache SANITIZER_MIN_OSX_VERSION
Subsequent times through:
* SANITIZER_MIN_OSX_VERSION is cached
* (BUG!!) you don't parse -mmacosx-version-min, and don't set
MACOSX_VERSION_MIN_FLAG
MACOSX_VERSION_MIN_FLAG is used later in the file on this line:
63c925ca80/compiler-rt/cmake/config-ix.cmake (L517)
Hoisting this assignment outside the if block returns us to the previous
behavior before this commit, while maintaining the flexibility
introduced with the cache variable