Remove catch_user_interfaces

It used to be a file that would collect interfaces we always wanted
to provide to users, so that the single header stitching script
would place them in the common part of the single header version.

As v3 is moving to separate headers model, the file is no longer
useful.

src/CMakeLists.txt

@@ -118,7 +118,6 @@ set(INTERNAL_HEADERS
     ${SOURCES_DIR}/catch_tostring.h
     ${SOURCES_DIR}/catch_totals.h
     ${SOURCES_DIR}/catch_uncaught_exceptions.h
-    ${SOURCES_DIR}/catch_user_interfaces.h
     ${SOURCES_DIR}/catch_version.h
     ${SOURCES_DIR}/catch_version_macros.hpp
     ${SOURCES_DIR}/catch_wildcard_pattern.h

src/catch2/catch_user_interfaces.h

@@ -1,18 +0,0 @@
-/*
- *  Created by Martin on 21/11/2017.
- *
- *  This file collects declaration that we want to expose to test files.
- *  These declarations are expected to be duplicated elsewhere,
- *  together with their implementation.
- *
- *  Distributed under the Boost Software License, Version 1.0. (See accompanying
- *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- */
-#ifndef TWOBLUECUBES_CATCH_USER_INTERFACES_H_INCLUDED
-#define TWOBLUECUBES_CATCH_USER_INTERFACES_H_INCLUDED
-
-namespace Catch {
-    unsigned int rngSeed();
-}
-
-#endif // TWOBLUECUBES_CATCH_USER_INTERFACES_H_INCLUDED