Merge pull request #80282 from Steelskin/fabrice/define-swift-stdlib-build-types-missing

Disable CompatibilitySpans outside of stdlib build

Author: slavapestov

stdlib/toolchain/CompatibilitySpan/CMakeLists.txt

@@ -1,4 +1,4 @@
-if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND DEFINED SWIFT_STDLIB_LIBRARY_BUILD_TYPES)
 
   set(library_name "swiftCompatibilitySpan")
 
@@ -31,4 +31,4 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
     LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}" -Xlinker -not_for_dyld_shared_cache
 
     BACK_DEPLOYMENT_LIBRARY 6.2)
-endif()
+endif()