To avoid the following error message (using cmake version 3.13.4) :
```
CMake Error at tools/llvm-config/CMakeLists.txt:37 (string):
Syntax error in cmake code when parsing string-std=[^ ]\+Invalid escape sequence \+
```
Reviewed By: mgorny
Differential Revision: https://reviews.llvm.org/D58619
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@369887
91177308-0d34-0410-b5e6-
96231b3b80d8
# NOTE: We don't want to start extracting any random C/CXX flags that the
# user may add that could affect the ABI. We only want to extract flags
# that have been added by the LLVM build system.
-string(REGEX MATCH "-std=[^ ]\+" LLVM_CXX_STD_FLAG ${CMAKE_CXX_FLAGS})
-string(REGEX MATCH "-stdlib=[^ ]\+" LLVM_CXX_STDLIB_FLAG ${CMAKE_CXX_FLAGS})
-string(REGEX MATCH "-std=[^ ]\+" LLVM_C_STD_FLAG ${CMAKE_C_FLAGS})
+string(REGEX MATCH "-std=[^ ]+" LLVM_CXX_STD_FLAG ${CMAKE_CXX_FLAGS})
+string(REGEX MATCH "-stdlib=[^ ]+" LLVM_CXX_STDLIB_FLAG ${CMAKE_CXX_FLAGS})
+string(REGEX MATCH "-std=[^ ]+" LLVM_C_STD_FLAG ${CMAKE_C_FLAGS})
# Use configure_file to create BuildVariables.inc.
set(LLVM_SRC_ROOT ${LLVM_MAIN_SRC_DIR})