* builds/detect.mk (TOP_DIR), builds/os2/os2-dev.mk (TOP_DIR), builds/win32/w32-dev.mk (TOP_DIR): Removed. Defined elsewhere.
* builds/dos/dos-emx.mk, builds/compiler/emx.mk: New files for EMX gcc compiler. * builds/dos/detect.mk: Add target `emx'. * builds/compiler/watcom.mk (LINK_LIBRARY): GNU Make for DOS doesn't like a trailing semicolon; add a dummy command.