Remove unused headers

With help from
https://github.com/include-what-you-use/include-what-you-use/

libi3/draw_util.c

@@ -8,8 +8,6 @@
  */
 #include "libi3.h"
 
-#include <cairo/cairo-xcb.h>
-#include <err.h>
 #include <stdlib.h>
 #include <string.h>
 

libi3/fake_configure_notify.c

@@ -7,7 +7,6 @@
  */
 #include "libi3.h"
 
-#include <stdbool.h>
 #include <stdlib.h>
 
 #include <xcb/xcb.h>

libi3/font.c

@@ -11,7 +11,6 @@
 #include <cairo/cairo-xcb.h>
 #include <err.h>
 #include <pango/pangocairo.h>
-#include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>

libi3/format_placeholders.c

@@ -7,7 +7,6 @@
  */
 #include "libi3.h"
 
-#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 

libi3/get_exe_path.c

@@ -8,8 +8,6 @@
 #include "libi3.h"
 
 #include <errno.h>
-#include <limits.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

libi3/get_process_filename.c

@@ -7,15 +7,10 @@
  */
 #include "libi3.h"
 
-#include <assert.h>
 #include <err.h>
 #include <pwd.h>
-#include <stdbool.h>
-#include <stdint.h>
 #include <stdlib.h>
-#include <string.h>
 #include <sys/stat.h>
-#include <sys/types.h>
 #include <unistd.h>
 
 /*

libi3/ipc_connect.c

@@ -12,9 +12,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
-#include <sys/types.h>
 #include <sys/un.h>
-#include <unistd.h>
 
 /*
  * Connects to the i3 IPC socket and returns the file descriptor for the

libi3/ipc_recv_message.c

@@ -11,8 +11,6 @@
 #include <i3/ipc.h>
 #include <inttypes.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 

libi3/ipc_send_message.c

@@ -7,13 +7,8 @@
  */
 #include "libi3.h"
 
-#include <err.h>
-#include <errno.h>
 #include <i3/ipc.h>
 #include <stdint.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
 
 /*
  * Formats a message (payload) of the given size and type and sends it to i3 via

libi3/is_debug_build.c

@@ -7,7 +7,6 @@
  */
 #include "libi3.h"
 
-#include <stdbool.h>
 #include <string.h>
 
 /*

libi3/root_atom_contents.c

@@ -7,10 +7,7 @@
  */
 #include "libi3.h"
 
-#include <limits.h>
 #include <math.h>
-#include <stdbool.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 

libi3/safewrappers.c

@@ -9,8 +9,6 @@
 
 #include <err.h>
 #include <errno.h>
-#include <stdarg.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

libi3/strndup.c

@@ -8,7 +8,6 @@
 #include "libi3.h"
 
 #include <string.h>
-#include <sys/types.h>
 
 #ifndef HAVE_strndup
 /*

libi3/ucs2_conversion.c

@@ -8,7 +8,6 @@
 #include "libi3.h"
 
 #include <err.h>
-#include <errno.h>
 #include <iconv.h>
 #include <stdlib.h>
 #include <string.h>