On Cygwin, use /proc file system instead of win32 API. * lib/relocatable.c: On Cygwin, use file names from /proc, rather than Win32 file names. (DllMain): Simplify by removing Cygwin specific code. (find_shared_library_fullname): Use Linux specific implementation also for Cygwin. (get_shared_library_fullname): Update accordingly. * lib/progreloc.c: On Cygwin, use file names from /proc, rather than Win32 file names. (find_executable): On Cygwin, use /proc, like on Linux. Remove previous Cygwin specific code.