README: Add "make deplibs" to quick build section.

pfalcon · pfalcon · commit e66b3042d6a6 · 2016-05-28T20:41:39.000+03:00
diff --git a/README.md b/README.md
@@ -71,6 +71,7 @@ Alternatively, fallback implementation based on setjmp/longjmp can be used.
 To build (see section below for required dependencies):
 
     $ cd unix
+    $ make deplibs
     $ make
 
 Then to give it a try:
