Do not use tr1 with libc++

clang defines __GNUC__ but libc++ does not have tr1, so we either need to use
boost, or std and compile in c++11 mode.

diff --git a/configure.ac b/configure.ac
index 3b29b38257c663413ab2e8a0ef63ca2b2c697be9..1cbb6bd978ab9d175a66f4aa29e2ed5d9c78588a 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -285,8 +285,9 @@ char * strerror(int n);
 #define BOOST_SIGNALS_NO_DEPRECATION_WARNING 1
 
 // TR1 regex not supported in GCC <= 4.5
+// clang defines __GNUC__ but libc++ does not have tr1
 #ifndef LYX_USE_TR1
-#  if __GNUC__ == 4 
+#  if __GNUC__ == 4 && !defined(USE_LLVM_LIBCPP)
 #    define LYX_USE_TR1
 #  endif
 #endif