[CMake] Copy folder without permissions

Copying the folder keeps the original permissions by default. This
creates problems when the source folder is read-only, e.g. in a
packaging environment.
Then, the copied folder in the build directory is read-only as well.
Later on, other files are copied into that directory (in the build
tree), failing when the directory is read-only.

Fix that problem by copying the folder without keeping the original
permissions.

Follow-up to D130254.

Differential Revision: https://reviews.llvm.org/D130338

clang/cmake/modules/CMakeLists.txt

@@ -32,7 +32,8 @@ set(CLANG_CONFIG_LLVM_CMAKE_DIR)
 
 # For compatibility with projects that include(ClangConfig)
 # via CMAKE_MODULE_PATH, place API modules next to it.
-# Copy without source permissions because the source could be read-only
+# Copy without source permissions because the source could be read-only,
+# but we need to write into the copied folder.
 file(COPY .
   DESTINATION ${clang_cmake_builddir}
   NO_SOURCE_PERMISSIONS

llvm/cmake/modules/CMakeLists.txt

@@ -99,9 +99,12 @@ set(llvm_config_include_buildtree_only_exports)
 
 # For compatibility with projects that include(LLVMConfig)
 # via CMAKE_MODULE_PATH, place API modules next to it.
+# Copy without source permissions because the source could be read-only,
+# but we need to write into the copied folder.
 # This should be removed in the future.
 file(COPY .
   DESTINATION ${llvm_cmake_builddir}
+  NO_SOURCE_PERMISSIONS
   FILES_MATCHING PATTERN *.cmake
   PATTERN CMakeFiles EXCLUDE
   )

mlir/cmake/modules/CMakeLists.txt

@@ -42,9 +42,12 @@ set(MLIR_CONFIG_INCLUDE_DIRS)
 
 # For compatibility with projects that include(MLIRConfig)
 # via CMAKE_MODULE_PATH, place API modules next to it.
+# Copy without source permissions because the source could be read-only,
+# but we need to write into the copied folder.
 # This should be removed in the future.
 file(COPY .
   DESTINATION ${mlir_cmake_builddir}
+  NO_SOURCE_PERMISSIONS
   FILES_MATCHING PATTERN *.cmake
   PATTERN CMakeFiles EXCLUDE
   )