Un-set CMAKE_C_COMPILER_LAUNCHER and CMAKE_CXX_COMPILER_LAUNCHER in s… (#23806)

[CMake] Add check for distcc before setting CMAKE_C_COMPILER_LAUNCHER and CMAKE_CXX_COMPILER_LAUNCHER

Author: shahmishal

stdlib/CMakeLists.txt

@@ -29,8 +29,12 @@ else()
     set(CMAKE_C_COMPILER "${SWIFT_NATIVE_LLVM_TOOLS_PATH}/clang")
   endif()
 
-  set(CMAKE_C_COMPILER_LAUNCHER "")
-  set(CMAKE_CXX_COMPILER_LAUNCHER "")
+  if(CMAKE_C_COMPILER_LAUNCHER MATCHES ".*distcc")
+    set(CMAKE_C_COMPILER_LAUNCHER "")
+  endif()
+  if(CMAKE_CXX_COMPILER_LAUNCHER MATCHES ".*distcc")
+    set(CMAKE_CXX_COMPILER_LAUNCHER "")
+  endif()
 
   # The sanitizers require using the same version of the compiler for
   # everything and there are various places where we link runtime code with

unittests/runtime/CMakeLists.txt

@@ -20,8 +20,12 @@ if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
       set(CMAKE_C_COMPILER "${SWIFT_NATIVE_LLVM_TOOLS_PATH}/clang")
     endif()
 
-    set(CMAKE_C_COMPILER_LAUNCHER "")
-    set(CMAKE_CXX_COMPILER_LAUNCHER "")
+    if(CMAKE_C_COMPILER_LAUNCHER MATCHES ".*distcc")
+      set(CMAKE_C_COMPILER_LAUNCHER "")
+    endif()
+    if(CMAKE_CXX_COMPILER_LAUNCHER MATCHES ".*distcc")
+      set(CMAKE_CXX_COMPILER_LAUNCHER "")
+    endif()
   endif()
 
   set(swift_runtime_test_extra_libraries)