Improve 1989/jar.2/try.sh

Allow CC to be set and used for compilation.

1989/jar.2/Makefile

@@ -132,7 +132,6 @@ all: data ${TARGET}
 
 ${PROG}: ${PROG}.c
 	${CC} ${CFLAGS} $< -o $@ ${LDFLAGS}
-	@echo
 	@echo NOTE: invalid input will cause this entry to dump core. See README.md for details.
 
 # alternative executable

1989/jar.2/try.sh

@@ -1,8 +1,15 @@
 #!/usr/bin/env bash
 # 
 # demo for 1989/jar.2 - run entry with one or more files
+#
 
-make all || exit 1
+# if CC is not specified set to default 'cc'. CC can be a path or no path which
+# makes the shell figure it out.
+if [[ -z "$CC" ]]; then
+    CC="cc"
+fi
+
+make CC="$CC" all || exit 1
 
 if [[ "$#" -lt 1 ]]; then
     FILES="try.txt fib.lisp chocolate_cake.lisp"
@@ -12,6 +19,7 @@ fi
 
 for f in $FILES; do 
     if [[ -e "$f" && -r "$f" ]]; then
+	echo "$ ./jar.2 < $f" 1>&2
 	./jar.2 < "$f"
     fi
 done