Correctly set WEBGL macro during pas2c conversion

Disable stereo rendering when compiled with pas2c

Fully support emscripten toolchain in our build system

Import the Emscripted toolchain configuration

Hijack SDL2 and GLEW include and library when compiling to javascript emscripten already provides the SDL2 suite and will simply ignore missing libraries.

Work around how emscripten defines rwops

Work around emscripten not finding math.h

Add support for compiling C engine with emscripten

travis: Use latest cmake vailable

Fix fpcrtl_strappendA, which cut last char from UserPathPrefix leading to PHYSFS_setWriteDir fail with 'File not found' error, which led to lack of writing dir and logFile handle being nil, which led to crash on attempt to write to (absent) log file

missing comma

Use our copy for border too

SDL blit wraps at 16,384 - not the first time that routine has disappointed us.

merge

Allow variable boost directions in Racer

Fixes crash Wuzzy and I were encountering in debian fpc 2.6.2 and 3.0.0 after the addition of the uPhysFSLayer dependency to uUtils in rcac74d9075be