config: prevent the re-definition of a macro

This causes unnecessary warnings when building with `cl`.  Newer
versions of the C standard permit the redefinition of the macro to the
same value (which is the case here), unfortunately, `cl` does not yet
implement this.  Add a check to prevent the redefinition.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@293439 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Saleem Abdulrasool 2017-01-29 18:16:33 +00:00
parent 362353aa2d
commit bc116591fd

View File

@ -12,8 +12,10 @@
#define _LIBCPP_CONFIG
#if defined(_MSC_VER) && !defined(__clang__)
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#define _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#endif
#endif
#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#pragma GCC system_header