Previously, we would activate the debugger (if enabled), and then
reactivate the main window. This meant if you switched to something,
PPSSPP would demand focus once the game loaded.
Add missing #include to various files.
strings.h isn't provided by MSVC so we don't include it there; it's needed
for other OSes/compilers.
Get rid of pre-ISO-C malloc.h includes; malloc is provided by stdlib.h.
Fixes some linuxisms.
Prepend __builtin_ to __clear_cache, calling it without the prefix is a
GNU extension.
