Properly configure the target library name used by magic-symbols-for-install-name.c.

Author: mikeash

cmake/modules/AddSwift.cmake

@@ -1881,10 +1881,13 @@ function(add_swift_target_library name)
       endforeach()
 
       # Add PrivateFrameworks, rdar://28466433
+      set(swiftlib_c_compile_flags_all ${SWIFTLIB_C_COMPILE_FLAGS})
       if(sdk IN_LIST SWIFT_APPLE_PLATFORMS AND SWIFTLIB_IS_SDK_OVERLAY)
         set(swiftlib_swift_compile_private_frameworks_flag "-Fsystem" "${SWIFT_SDK_${sdk}_ARCH_${arch}_PATH}/System/Library/PrivateFrameworks/")
       endif()
 
+      list(APPEND swiftlib_c_compile_flags_all "-DSWIFT_TARGET_LIBRARY_NAME=${name}")
+
       # Add this library variant.
       _add_swift_library_single(
         ${VARIANT_NAME}
@@ -1902,7 +1905,7 @@ function(add_swift_target_library name)
         FRAMEWORK_DEPENDS_WEAK ${SWIFTLIB_FRAMEWORK_DEPENDS_WEAK}
         LLVM_COMPONENT_DEPENDS ${SWIFTLIB_LLVM_COMPONENT_DEPENDS}
         FILE_DEPENDS ${SWIFTLIB_FILE_DEPENDS} ${swiftlib_module_dependency_targets}
-        C_COMPILE_FLAGS ${SWIFTLIB_C_COMPILE_FLAGS}
+        C_COMPILE_FLAGS ${swiftlib_c_compile_flags_all}
         SWIFT_COMPILE_FLAGS ${swiftlib_swift_compile_flags_all} ${swiftlib_swift_compile_flags_arch} ${swiftlib_swift_compile_private_frameworks_flag}
         LINK_FLAGS ${swiftlib_link_flags_all}
         PRIVATE_LINK_LIBRARIES ${swiftlib_private_link_libraries_targets}