Added info about include X11 in ubuntu.
Added comment with X11 path in systems based on ubuntu.
@@ -10,6 +10,10 @@ MANPREFIX = $(PREFIX)/share/man
X11INC = /usr/X11R6/include
X11LIB = /usr/X11R6/lib
+# include X11 in Ubuntu
+# X11INC = /usr/include/X11R6
+# X11LIB = /usr/lib/X11R6
+
PKG_CONFIG = pkg-config
# includes and libs
