various shell script fixes.

add 9a, 9c, 9l wrapper scripts.
label sets label on xterm/9term

bin/9c

@@ -0,0 +1,33 @@
+#!/bin/sh
+
+usegcc()
+{
+	cc=gcc
+	cflags=" \
+		-O2 \
+		-I$PLAN9/include \
+		-c \
+		-ggdb \
+		-Wall \
+		-Wno-parentheses \
+		-Wno-missing-braces \
+		-Wno-switch \
+	"
+}
+
+cc=none
+tag="`uname`-`uname -m`-${CC:-cc}"
+case "$tag" in
+*BSD*)		usegcc ;;
+*Darwin*)	usegcc ;;
+*HP-UX*)	cc=cc; cflags="-g -O -c -Ae" ;;
+*Linux*)	usegcc ;;
+*OSF1*)		cc=cc; cflags="-g -O -c" ;;
+*SunOS*-cc)	cc=cc; cflags="-g -O -c -xCC -D__sun__" ;;
+*SunOS*-gcc)	usegcc ;;
+*)
+	echo 9c does not know how to compile on "$tag" 1>&2
+	exit 1
+esac
+
+exec cc $cflags "$@"