build: Add instructions to build gui in default make
build: Add instructions to build gui in default make

Add the output:

 *** to build the gui, type "make gui" ***

to the end of the build when "make" is executed. This will let the
user know they need to do more to build the gui code.

Signed-off-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

bigzz/trace-cmd,bigzz/trace-cmd