Add the #goo to allow use in C++.

Silence a few more warnings.
Strip down the mkfiles more.
Fix bug in X11 mouse handling, note groups.

src/mkhdr

@@ -1,26 +1,25 @@
 SYSNAME=`uname`
 OBJTYPE=`uname -m | sed 's;i.86;386;; s;/.*;;; s; ;;g'`
 
-X11=/usr/X11R6
-CC=9c
-LD=9l
-AS=9a
-AR=9ar
-CFLAGS=
-LDFLAGS=
-AFLAGS=
-O=o
-
 BIN=$PLAN9/bin
 LIBDIR=$PLAN9/lib
 
-<|cat $PLAN9/src/mk.$SYSNAME-$OBJTYPE 2>/dev/null || true
+# BUG - figure this out automatically
+X11=/usr/X11R6
 
+O=o
 OS=$O
-LD=9l
-LDFLAGS=$LDFLAGS -L$LIBDIR
 
-CLEANFILES=*.$O
+CC=9c
+LD=9l
+AS=9a
+AR=9ar
+INSTALL=install -c
+CFLAGS=
+LDFLAGS=
+AFLAGS=
+CLEANFILES=
 NUKEFILES=
 
-INSTALL=install -c
+<|cat $PLAN9/src/mk.$SYSNAME-$OBJTYPE 2>/dev/null || true
+