Clang does not understand __attribute__((warning)), so don't use
it to tag experimental functions.

* subversion/include/svn_types.h (SVN_EXPERIMENTAL): Skip the GCC definition
   of this macro when compiling with clang.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1527773 13f79535-47bb-0310-9956-ffa450edef68