Do not apply patches if repo is a not a git repo.

Also backports fb75598

Author: haonanya1

cmake/modules/CMakeFunctions.cmake

@@ -102,10 +102,12 @@ function(apply_patches repo_dir patches_dir base_revision target_branch)
         COMMAND ${GIT_EXECUTABLE} rev-parse --verify --no-revs -q ${target_branch}
         WORKING_DIRECTORY ${repo_dir}
         RESULT_VARIABLE patches_needed
-        ERROR_QUIET
         OUTPUT_QUIET
     )
-    if(patches_needed) # The target branch doesn't exist
+    if(patches_needed EQUAL 128) # not a git repo
+      message(STATUS "[OPENCL-CLANG] ${repo_dir} is not a git repository")
+      return()
+     elseif(patches_needed EQUAL 1) # The target branch doesn't exist
         list(SORT patches)
         is_valid_revision(${repo_dir} ${base_revision} exists_base_rev)
 
@@ -115,7 +117,6 @@ function(apply_patches repo_dir patches_dir base_revision target_branch)
                 WORKING_DIRECTORY ${repo_dir}
                 OUTPUT_VARIABLE repo_head
                 OUTPUT_STRIP_TRAILING_WHITESPACE
-                ERROR_QUIET
                 )
             message(STATUS "[OPENCL-CLANG] ref ${base_revision} not exists in repository, using current HEAD:${repo_head}")
             set(base_revision ${repo_head})
@@ -135,22 +136,23 @@ function(apply_patches repo_dir patches_dir base_revision target_branch)
                 message(STATUS "[OPENCL-CLANG] Patch ${patch} is already in local branch - ignore patching")
             else()
                 execute_process( # Apply the patch
-                    COMMAND ${GIT_EXECUTABLE} am --3way --ignore-whitespace ${patch}
+                    COMMAND ${GIT_EXECUTABLE} am --3way --ignore-whitespace -C0 ${patch}
                     WORKING_DIRECTORY ${repo_dir}
                     OUTPUT_VARIABLE patching_log
-                    ERROR_QUIET
                 )
                 message(STATUS "[OPENCL-CLANG] Not present - ${patching_log}")
             endif()
         endforeach(patch)
-    else() # The target branch already exists
+    elseif(patches_needed EQUAL 0) # The target branch already exists
         execute_process( # Check it out
             COMMAND ${GIT_EXECUTABLE} checkout ${target_branch}
             WORKING_DIRECTORY ${repo_dir}
-            ERROR_QUIET
             OUTPUT_QUIET
         )
     endif()
+    if (ret_check_out OR ret_apply_patch)
+      message(FATAL_ERROR "[OPENCL-CLANG] Failed to apply patch!")
+    endif()
 endfunction()
 
 # Usage