[LyX/master] Extend Clang compiler detection to cover Apple CLang

[Stephan Witt]

commit 1bf4d7b0fc2bc4c700e7cecc1e6e3c7faf4f03a5
Author: Stephan Witt <sw...@lyx.org>
Date:   Tue Jun 12 22:42:48 2018 +0200

    Extend Clang compiler detection to cover Apple CLang
    
    CMake 3.0 and above recognize that Apple Clang is a different compiler than 
upstream Clang and so it gets a different CMAKE_CXX_COMPILER_ID.
---
 CMakeLists.txt                                    |    2 +-
 development/cmake/modules/FindCXX11Compiler.cmake |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d1b448c..63b4ea2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -260,7 +260,7 @@ if(NOT CXX11COMPILER_FOUND)
 endif()
 set(LYX_GCC11_MODE)
 if(UNIX OR MINGW)
-       if (CMAKE_CXX_COMPILER_ID MATCHES "^[cC]lang$")
+       if (CMAKE_CXX_COMPILER_ID MATCHES "^([cC]lang|AppleClang)$")
          # ignore the GCC_VERSION for clang
          # and use the resulting CXX11_STD_REGEX found in 
FindCXX11Compiler.cmake
          message(STATUS "Using clang")
diff --git a/development/cmake/modules/FindCXX11Compiler.cmake 
b/development/cmake/modules/FindCXX11Compiler.cmake
index 5c7b698..739d267 100644
--- a/development/cmake/modules/FindCXX11Compiler.cmake
+++ b/development/cmake/modules/FindCXX11Compiler.cmake
@@ -34,7 +34,7 @@
 INCLUDE(CheckCXXSourceCompiles)
 INCLUDE(FindPackageHandleStandardArgs)
 
-if (CMAKE_CXX_COMPILER_ID MATCHES "^[cC]lang$")
+if (CMAKE_CXX_COMPILER_ID MATCHES "^([cC]lang|AppleClang)$")
   set(CXX11_FLAG_CANDIDATES "--std=c++11 -Wno-deprecated-register")
 else()
   if (CYGWIN)