* cygheap.cc (init_cygheap::init_installation_root): Install Cygwin's

	* cygheap.cc (init_cygheap::init_installation_root): Install Cygwin's
	installation dir as DLL search path, instead of ".".
	* cygheap.h (class cwdstuff): Add parameter names in function
	declarations for readability.
	(cwdstuff::get): Ad inline implementation fetching the CWD as wide char
	string.
	* dlfcn.cc (dlopen): Add searching for dependent DLLs in DLL
	installation dir or CWD, if all else failed.
	Add comment to explain scenarios this is accommodating.