libroot/glibc: Include the private stdio headers and declare more private methods there.

Fixes implicit-function-declaration errors.

src/system/libroot/posix/glibc/include/stdio_private.h

@@ -27,6 +27,13 @@ extern int __vsscanf (__const char *__restrict __s,
 		      _G_va_list __arg)
      __attribute__ ((__format__ (__scanf__, 2, 0)));
 
+extern int __printf_fp (FILE *fp,
+	 const struct printf_info *info,
+	 const void *const *args);
+extern int __printf_fphex (FILE *fp,
+	const struct printf_info *info,
+	const void *const *args);
+
 /* Prototypes for compatibility functions.  */
 extern FILE *__new_tmpfile (void);
 extern FILE *__old_tmpfile (void);

src/system/libroot/posix/glibc/misc/efgcvt_r.c

@@ -19,7 +19,7 @@
 
 #include <errno.h>
 #include <float.h>
-#include <stdio.h>
+#include <stdio_private.h>
 #include <string.h>
 #include <ctype.h>
 #include <math.h>

src/system/libroot/posix/glibc/stdio-common/fscanf.c

@@ -17,7 +17,7 @@
    02111-1307 USA.  */
 
 #include <stdarg.h>
-#include <stdio.h>
+#include <stdio_private.h>
 
 /* Read formatted input from STREAM according to the format string FORMAT.  */
 /* VARARGS2 */

src/system/libroot/posix/glibc/stdio-common/printf_size.c

@@ -88,10 +88,6 @@ ssize_t __printf_pad __P ((FILE *, char pad, int n)); /* In vfprintf.c.  */
     }									      \
   while (0)
 
-/* Prototype for helper functions.  */
-extern int __printf_fp (FILE *fp, const struct printf_info *info,
-			const void *const *args);
-
 
 int
 printf_size (FILE *fp, const struct printf_info *info, const void *const *args)

src/system/libroot/posix/glibc/stdio-common/vfprintf.c

@@ -29,7 +29,7 @@
 #include <sys/param.h>
 #include "_itoa.h"
 #include <locale/localeinfo.h>
-#include <stdio.h>
+#include <stdio_private.h>
 
 /* This code is shared between the standard stdio implementation found
    in GNU C library and the libio implementation originally found in