Don't include warning headers from catch_xmlwriter.hpp

This prevents Catch from disabling `Wpadded` for Clang inside test files
(files that do not define either `CATCH_CONFIG_MAIN` or
`CATCH_CONFIG_RUNNER`).

catch_suppress_warnings.h and catch_reenable_warnings.h should be
included only once*, so that the stitching script includes them as the
first and last header respectively, since it only includes each header
once. This caused a bug, where the first one was included properly, but
the second one was included prematurely, from catch_xmlwriter.hpp, and
thus was guarded by `CATCH_IMPL`.

* At least until the stitching script is changed to accomodate common
warning disabling header.

Fixes #871

0 files changed, 0 insertions, 0 deletions