Remove extraneous external/forward declarations that are duplicates of those in "xxxdefs.h" files.

modified:   src/allocmds.c
	modified:   src/array5.c
	modified:   src/car-cdr.c
	modified:   src/dbgtool.c
	modified:   src/ether.c
	modified:   src/gc2.c
	modified:   src/gcfinal.c
	modified:   src/gcmain3.c
	modified:   src/gcrcell.c
	modified:   src/initkbd.c
	modified:   src/initsout.c
	modified:   src/keyevent.c
	modified:   src/keylib.c
	modified:   src/keymaker.c
	modified:   src/keytst.c
	modified:   src/loopsops.c
	modified:   src/lsthandl.c
	modified:   src/main.c
	modified:   src/mkatom.c
	modified:   src/mkcell.c
	modified:   src/mvs.c
	modified:   src/storage.c
	modified:   src/testtool.c
	modified:   src/unixcomm.c
	modified:   src/vars3.c
	modified:   src/xc.c
	modified:   src/z2.c

src/ether.c

@@ -361,8 +361,6 @@ LispPTR ether_reset(LispPTR args[])
 /*	it's OK to read packets from the network on interrupt.		*/
 /*									*/
 /************************************************************************/
-LispPTR get_packet();
-
 LispPTR ether_get(LispPTR args[])
 {
   LispPTR MaxByteCount;