Fix fallback define for DECLSPEC for non-Windows platforms.
Looks like it was a copy/paste error?
GCC doesn't support visibility attributes until gcc4, so just make it blank.
Fixes Bugzilla #2720.
Windows: Always set the system timer resolution to 1ms by default.
An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.
Fixes Bugzilla #2944.