shorter copyright notice and moved back VERSION and _GNU_SOURCE as the man page version number fails

config.mk

@@ -1,3 +1,7 @@
+# See LICENSE file for copyright and license details.
+
+VERSION = 2.0
+
 PREFIX = /usr/local
 MANPREFIX = ${PREFIX}/share/man
 
@@ -7,6 +11,7 @@ X11LIB = /usr/X11R6/lib
 INCS = -I. -I/usr/include -I${X11INC}
 LIBS = -L/usr/lib -lc -L${X11LIB} -lX11 -lasound
 
+CPPFLAGS = -DVERSION=\"${VERSION}\" -D_GNU_SOURCE
 # -Wno-unused-function for routines not activated by user
 CFLAGS = -std=c99 -pedantic -Wno-unused-function -Wall -Wextra -Os ${INCS} ${CPPFLAGS}
 LDFLAGS = ${LIBS}

slstatus.c

@@ -1,11 +1,4 @@
-/*
- * Copyright (C) 2016, drkhsh
- * Copyright (C) 2016, Ali H. Fardan (Raiz) <raiz@firemail.cc>
- * see LICENSE for copyright details
- */
-
-#define _GNU_SOURCE
-#define VERSION "2.0"
+/* See LICENSE file for copyright and license details. */
 
 #include <alsa/asoundlib.h>
 #include <err.h>