Ensure all *.[ch] files include config.h

Including config.h is necessary to get e.g. the _GNU_SOURCE define and
any other definitions that autoconf declares. Hence, config.h needs to
be included as the first header in each file.

This is done either via:
1. Including "common.h" (i3bar)
2. Including "libi3.h"
3. Including "all.h" (i3)
4. Including <config.h> directly

Also remove now-unused I3__FILE__, add copyright/license statement
where missing and switch include/all.h to #pragma once.

i3bar/src/child.c

@@ -7,6 +7,8 @@
  * child.c: Getting input for the statusline
  *
  */
+#include "common.h"
+
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/types.h>
@@ -25,8 +27,6 @@
 #include <yajl/yajl_gen.h>
 #include <paths.h>
 
-#include "common.h"
-
 /* Global variables for child_*() */
 i3bar_child child;
 

i3bar/src/config.c

@@ -7,6 +7,8 @@
  * config.c: Parses the configuration (received from i3).
  *
  */
+#include "common.h"
+
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -17,8 +19,6 @@
 
 #include <X11/Xlib.h>
 
-#include "common.h"
-
 static char *cur_key;
 static bool parsing_bindings;
 static bool parsing_tray_outputs;

i3bar/src/ipc.c

@@ -7,6 +7,8 @@
  * ipc.c: Communicating with i3
  *
  */
+#include "common.h"
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -21,8 +23,6 @@
 #include <sanitizer/lsan_interface.h>
 #endif
 
-#include "common.h"
-
 ev_io *i3_connection;
 
 const char *sock_path;

i3bar/src/main.c

@@ -5,6 +5,8 @@
  * © 2010 Axel Wagner and contributors (see also: LICENSE)
  *
  */
+#include "common.h"
+
 #include <stdio.h>
 #include <i3/ipc.h>
 #include <string.h>
@@ -15,8 +17,6 @@
 #include <getopt.h>
 #include <glob.h>
 
-#include "common.h"
-
 /*
  * Having verboselog(), errorlog() and debuglog() is necessary when using libi3.
  *

i3bar/src/mode.c

@@ -7,6 +7,8 @@
  * mode.c: Handle mode event and show current binding mode in the bar
  *
  */
+#include "common.h"
+
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -14,8 +16,6 @@
 #include <yajl/yajl_parse.h>
 #include <yajl/yajl_version.h>
 
-#include "common.h"
-
 /* A datatype to pass through the callbacks to save the state */
 struct mode_json_params {
     char *json;

i3bar/src/outputs.c

@@ -7,6 +7,8 @@
  * outputs.c: Maintaining the outputs list
  *
  */
+#include "common.h"
+
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -15,8 +17,6 @@
 #include <yajl/yajl_parse.h>
 #include <yajl/yajl_version.h>
 
-#include "common.h"
-
 /* A datatype to pass through the callbacks to save the state */
 struct outputs_json_params {
     struct outputs_head *outputs;

i3bar/src/parse_json_header.c

@@ -8,6 +8,8 @@
  *                      protocol version and features.
  *
  */
+#include "common.h"
+
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/types.h>
@@ -25,8 +27,6 @@
 #include <yajl/yajl_parse.h>
 #include <yajl/yajl_version.h>
 
-#include "common.h"
-
 static enum {
     KEY_VERSION,
     KEY_STOP_SIGNAL,

i3bar/src/workspaces.c

@@ -7,6 +7,8 @@
  * workspaces.c: Maintaining the workspace lists
  *
  */
+#include "common.h"
+
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -14,8 +16,6 @@
 #include <yajl/yajl_parse.h>
 #include <yajl/yajl_version.h>
 
-#include "common.h"
-
 /* A datatype to pass through the callbacks to save the state */
 struct workspaces_json_params {
     struct ws_head *workspaces;

i3bar/src/xcb.c

@@ -7,6 +7,8 @@
  * xcb.c: Communicating with X
  *
  */
+#include "common.h"
+
 #include <xcb/xcb.h>
 #include <xcb/xkb.h>
 #include <xcb/xproto.h>
@@ -32,7 +34,6 @@
 #include <sanitizer/lsan_interface.h>
 #endif
 
-#include "common.h"
 #include "libi3.h"
 
 /** This is the equivalent of XC_left_ptr. I’m not sure why xcb doesn’t have a