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/unixcomm.c

@@ -399,8 +399,6 @@ int FindAvailablePty(char *Master, char *Slave) {
 return (-1);
 }
 
-void WriteLispStringToPipe(LispPTR lispstr);
-
 /************************************************************************/
 /*                                                                      */
 /*  U n i x _ h a n d l e c o m m                                       */