[CMake][XRay] Silence llvm-config error when checking library support

Otherwise this propagates all the way to CMake and results in an error
during configuration. We check and handle the result and report warning
separately so this is not changing the behavior.

Differential Revision: https://reviews.llvm.org/D58086

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@353784 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/Modules/CompilerRTUtils.cmake

@@ -233,7 +233,8 @@ macro(load_llvm_config)
     execute_process(
       COMMAND ${LLVM_CONFIG_PATH} "--ldflags" "--libs" "xray"
       RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE CONFIG_OUTPUT)
+      OUTPUT_VARIABLE CONFIG_OUTPUT
+      ERROR_QUIET)
     if (HAD_ERROR)
       message(WARNING "llvm-config finding xray failed with status ${HAD_ERROR}")
       set(COMPILER_RT_HAS_LLVMXRAY FALSE)
@@ -250,7 +251,8 @@ macro(load_llvm_config)
     execute_process(
       COMMAND ${LLVM_CONFIG_PATH} "--ldflags" "--libs" "testingsupport"
       RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE CONFIG_OUTPUT)
+      OUTPUT_VARIABLE CONFIG_OUTPUT
+      ERROR_QUIET)
     if (HAD_ERROR)
       message(WARNING "llvm-config finding testingsupport failed with status ${HAD_ERROR}")
     else()