Swap include order to fix build with old MinGW-w64

There is a conflicting definition of some intrinsic functions in the
MinGW-w64 headers when included as both extern "C" and C++ in the same
file, which has since been fixed, but the broken version is bundled in
e.g. the version in Debian Jessie.
deps: default make to 2 threads
deps/enet: remove SDL cruft
Add -static to Win32 build options

This causes libwinpthread to be statically linked on newer MinGW-w64
versions.
deps: enable zlib for FreeType

zlib is already linked in anyway, so it doesn't add much bloat.

This also fixes an issue with the latest FreeType version where zlib is
required by other modules even when it's not enabled.
deps: add our include and lib directories

Also clean up the log summary and add the detected CC and other tools.
deps: use path-clean separator for sed

Previously, s// was used in several places where paths could be
specified as the replacement, which broke any time a slash was included
in the path.  Use | instead of / in these cases.
deps: define CMAKE_SYSTEM_PROCESSOR
deps: rename make_flags to MAKEFLAGS
deps: generate CMake cache file
README: Update cross-compile instructions