Remove a number of unused includes

csi.c

@@ -3,7 +3,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <errno.h>
 
 #if defined(_DEBUG)
  #include <stdio.h>

main.c

@@ -1,7 +1,6 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include <ctype.h>
 #include <stdbool.h>
 #include <limits.h>
 #include <locale.h>
@@ -36,8 +35,6 @@
 #include "xmalloc.h"
 #include "xsnprintf.h"
 
-#include "char32.h"
-
 #if !defined(__STDC_UTF_32__) || !__STDC_UTF_32__
  #error "char32_t does not use UTF-32"
 #endif

render.c

@@ -1,7 +1,6 @@
 #include "render.h"
 
 #include <string.h>
-#include <wctype.h>
 #include <unistd.h>
 #include <signal.h>
 

server.c

@@ -18,7 +18,6 @@
 #include "log.h"
 
 #include "client-protocol.h"
-#include "shm.h"
 #include "terminal.h"
 #include "util.h"
 #include "wayland.h"

slave.c

@@ -19,7 +19,6 @@
 
 #include "debug.h"
 #include "macros.h"
-#include "terminal.h"
 #include "tokenize.h"
 #include "util.h"
 #include "xmalloc.h"

vt.c

@@ -17,7 +17,6 @@
 #include "dcs.h"
 #include "debug.h"
 #include "emoji-variation-sequences.h"
-#include "grid.h"
 #include "osc.h"
 #include "sixel.h"
 #include "util.h"