#DOCTEST_CONFIG_USE_IOSFWD
iosfwd
MSVC 2015: 20k after preprocessor - 7k loc (without the new lines) drags cstdio, cstring and many others
GCC 5 - 1k of code without new lines and stuff
clang and libc++ - 400 loc
catch.hpp
MSVC 2015: 85k after preprocessor - 42k loc (without the new lines)
doctest.h MSVC 2015: 2k after preprocessor - 250 loc (without the new lines)