Add Solaris specific declararions for dlfcn.

Add definitions to core.sys.posix.dlfcn and add new modul core.sys.solaris.dlfcn.
(cherry picked from commit 77a8c8aee32aabed8cf6aa3913f62ecda9feffac)

Conflicts:
	mak/COPY
	mak/MANIFEST
	mak/SRCS
	win32.mak
	win64.mak