clean up stdio_impl.h

this header evolved to facilitate the extremely lazy practice of
omitting explicit includes of the necessary headers in individual
stdio source files; not only was this sloppy, but it also increased
build time.

now, stdio_impl.h is only including the headers it needs for its own
use; any further headers needed by source files are included directly
where needed.

src/stdio/__fdopen.c

@@ -1,4 +1,10 @@
 #include "stdio_impl.h"
+#include <stdlib.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
 
 FILE *__fdopen(int fd, const char *mode)
 {

src/stdio/__fopen_rb_ca.c

@@ -1,4 +1,6 @@
 #include "stdio_impl.h"
+#include <fcntl.h>
+#include <string.h>
 
 FILE *__fopen_rb_ca(const char *filename, FILE *f, unsigned char *buf, size_t len)
 {

src/stdio/__stdio_read.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <sys/uio.h>
 #include <pthread.h>
 
 static void cleanup(void *p)

src/stdio/__stdio_write.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <sys/uio.h>
 #include <pthread.h>
 
 static void cleanup(void *p)

src/stdio/__stdout_write.c

@@ -1,4 +1,6 @@
 #include "stdio_impl.h"
+#include <termios.h>
+#include <sys/ioctl.h>
 
 size_t __stdout_write(FILE *f, const unsigned char *buf, size_t len)
 {

src/stdio/__string_read.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <string.h>
 
 size_t __string_read(FILE *f, unsigned char *buf, size_t len)
 {

src/stdio/fgetln.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <string.h>
 
 char *fgetln(FILE *f, size_t *plen)
 {

src/stdio/fgets.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <string.h>
 
 #define MIN(a,b) ((a)<(b) ? (a) : (b))
 

src/stdio/fgetwc.c

@@ -1,4 +1,6 @@
 #include "stdio_impl.h"
+#include <wchar.h>
+#include <errno.h>
 
 wint_t __fgetwc_unlocked(FILE *f)
 {

src/stdio/fgetws.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <wchar.h>
 
 wint_t __fgetwc_unlocked(FILE *);
 

src/stdio/fmemopen.c

@@ -1,4 +1,7 @@
 #include "stdio_impl.h"
+#include <errno.h>
+#include <string.h>
+#include <inttypes.h>
 
 struct cookie {
 	size_t pos, len, size;

src/stdio/fopen.c

@@ -1,4 +1,7 @@
 #include "stdio_impl.h"
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
 
 FILE *fopen(const char *restrict filename, const char *restrict mode)
 {

src/stdio/fputs.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <string.h>
 
 int fputs(const char *restrict s, FILE *restrict f)
 {

src/stdio/fputwc.c

@@ -1,4 +1,7 @@
 #include "stdio_impl.h"
+#include <wchar.h>
+#include <limits.h>
+#include <ctype.h>
 
 wint_t __fputwc_unlocked(wchar_t c, FILE *f)
 {

src/stdio/fputws.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <wchar.h>
 
 int fputws(const wchar_t *restrict ws, FILE *restrict f)
 {

src/stdio/fread.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <string.h>
 
 #define MIN(a,b) ((a)<(b) ? (a) : (b))
 

src/stdio/freopen.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <fcntl.h>
 
 /* The basic idea of this implementation is to open a new FILE,
  * hack the necessary parts of the new FILE into the old one, then

src/stdio/ftell.c

@@ -1,4 +1,6 @@
 #include "stdio_impl.h"
+#include <limits.h>
+#include <errno.h>
 
 off_t __ftello_unlocked(FILE *f)
 {

src/stdio/fwrite.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <string.h>
 
 size_t __fwritex(const unsigned char *restrict s, size_t l, FILE *restrict f)
 {

src/stdio/getdelim.c

@@ -1,4 +1,7 @@
 #include "stdio_impl.h"
+#include <string.h>
+#include <inttypes.h>
+#include <errno.h>
 
 #define MIN(a,b) ((a)<(b) ? (a) : (b))
 

src/stdio/gets.c

@@ -1,4 +1,6 @@
 #include "stdio_impl.h"
+#include <limits.h>
+#include <string.h>
 
 char *gets(char *s)
 {

src/stdio/getwc.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <wchar.h>
 
 wint_t getwc(FILE *f)
 {

src/stdio/getwchar.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <wchar.h>
 
 wint_t getwchar(void)
 {

src/stdio/open_memstream.c

@@ -1,4 +1,7 @@
 #include "stdio_impl.h"
+#include <errno.h>
+#include <limits.h>
+#include <string.h>
 
 struct cookie {
 	char **bufp;

src/stdio/open_wmemstream.c

@@ -1,4 +1,8 @@
 #include "stdio_impl.h"
+#include <wchar.h>
+#include <errno.h>
+#include <limits.h>
+#include <string.h>
 
 struct cookie {
 	wchar_t **bufp;

src/stdio/pclose.c

@@ -1,5 +1,6 @@
 #include "stdio_impl.h"
-#include "syscall.h"
+#include <errno.h>
+#include <unistd.h>
 
 int pclose(FILE *f)
 {

src/stdio/putwc.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <wchar.h>
 
 wint_t putwc(wchar_t c, FILE *f)
 {

src/stdio/putwchar.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <wchar.h>
 
 wint_t putwchar(wchar_t c)
 {

src/stdio/ungetwc.c

@@ -1,4 +1,8 @@
 #include "stdio_impl.h"
+#include <wchar.h>
+#include <limits.h>
+#include <ctype.h>
+#include <string.h>
 
 wint_t ungetwc(wint_t c, FILE *f)
 {

src/stdio/vfprintf.c

@@ -1,4 +1,13 @@
 #include "stdio_impl.h"
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+#include <string.h>
+#include <stdarg.h>
+#include <wchar.h>
+#include <inttypes.h>
+#include <math.h>
+#include <float.h>
 
 /* Some useful macros */
 

src/stdio/vfscanf.c

@@ -1,4 +1,3 @@
-#include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include <ctype.h>
@@ -9,6 +8,7 @@
 #include <errno.h>
 #include <math.h>
 #include <float.h>
+#include <inttypes.h>
 
 #include "stdio_impl.h"
 #include "shgetc.h"

src/stdio/vfwprintf.c

@@ -1,4 +1,11 @@
 #include "stdio_impl.h"
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+#include <string.h>
+#include <stdarg.h>
+#include <wchar.h>
+#include <inttypes.h>
 
 /* Convenient bit representation for modifier flags, which all fall
  * within 31 codepoints of the space character. */

src/stdio/vsnprintf.c

@@ -1,4 +1,8 @@
 #include "stdio_impl.h"
+#include <limits.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
 
 static size_t sn_write(FILE *f, const unsigned char *s, size_t l)
 {

src/stdio/vswprintf.c

@@ -1,4 +1,9 @@
 #include "stdio_impl.h"
+#include <limits.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+#include <wchar.h>
 
 struct cookie {
 	wchar_t *ws;

src/stdio/vswscanf.c

@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <wchar.h>
 
 static size_t wstring_read(FILE *f, unsigned char *buf, size_t len)
 {