[CMake] Provide the ability to skip stripping when generating dSYMs

For debugging it is useful to be able to generate dSYM files but not strip the executables. This change adds the ability to skip stripping by setting COMPILER_RT_EXTERNALIZE_DEBUGINFO_SKIP_STRIP=On.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@265057 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/cmake/Modules/AddCompilerRT.cmake b/cmake/Modules/AddCompilerRT.cmake
index 13b8533..6991009 100644
--- a/cmake/Modules/AddCompilerRT.cmake
+++ b/cmake/Modules/AddCompilerRT.cmake
@@ -362,6 +362,10 @@
     return()
   endif()
 
+  if(NOT COMPILER_RT_EXTERNALIZE_DEBUGINFO_SKIP_STRIP)
+    set(strip_command COMMAND xcrun strip -Sl $<TARGET_FILE:${name}>)
+  endif()
+
   if(APPLE)
     if(CMAKE_CXX_FLAGS MATCHES "-flto"
       OR CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE} MATCHES "-flto")
@@ -372,7 +376,7 @@
     endif()
     add_custom_command(TARGET ${name} POST_BUILD
       COMMAND xcrun dsymutil $<TARGET_FILE:${name}>
-      COMMAND xcrun strip -Sl $<TARGET_FILE:${name}>)
+      ${strip_command})
   else()
     message(FATAL_ERROR "COMPILER_RT_EXTERNALIZE_DEBUGINFO isn't implemented for non-darwin platforms!")
   endif()