use restrict everywhere it's required by c99 and/or posix 2008

to deal with the fact that the public headers may be used with pre-c99
compilers, __restrict is used in place of restrict, and defined
appropriately for any supported compiler. we also avoid the form
[restrict] since older versions of gcc rejected it due to a bug in the
original c99 standard, and instead use the form *restrict.

src/locale/iconv.c

@@ -139,7 +139,7 @@ static void put_32(unsigned char *s, unsigned c, int e)
 #define mbrtowc_utf8 mbrtowc
 #define wctomb_utf8 wctomb
 
-size_t iconv(iconv_t cd0, char **in, size_t *inb, char **out, size_t *outb)
+size_t iconv(iconv_t cd0, char **restrict in, size_t *restrict inb, char **restrict out, size_t *restrict outb)
 {
 	size_t x=0;
 	unsigned long cd = (unsigned long)cd0;

src/locale/strfmon.c

@@ -75,7 +75,7 @@ static ssize_t vstrfmon_l(char *s, size_t n, locale_t loc, const char *fmt, va_l
 	return s-s0;
 }
 
-ssize_t strfmon_l(char *s, size_t n, locale_t loc, const char *fmt, ...)
+ssize_t strfmon_l(char *restrict s, size_t n, locale_t loc, const char *restrict fmt, ...)
 {
 	va_list ap;
 	ssize_t ret;
@@ -88,7 +88,7 @@ ssize_t strfmon_l(char *s, size_t n, locale_t loc, const char *fmt, ...)
 }
 
 
-ssize_t strfmon(char *s, size_t n, const char *fmt, ...)
+ssize_t strfmon(char *restrict s, size_t n, const char *restrict fmt, ...)
 {
 	va_list ap;
 	ssize_t ret;

src/locale/strftime_l.c

@@ -1,7 +1,7 @@
 #include <locale.h>
 #include <time.h>
 
-size_t strftime_l(char *s, size_t n, const char *f, const struct tm *tm, locale_t l)
+size_t strftime_l(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm, locale_t l)
 {
 	return strftime(s, n, f, tm);
 }

src/locale/strxfrm.c

@@ -1,7 +1,7 @@
 #include <string.h>
 
 /* collate only by code points */
-size_t strxfrm(char *dest, const char *src, size_t n)
+size_t strxfrm(char *restrict dest, const char *restrict src, size_t n)
 {
 	size_t l = strlen(src);
 	if (n > l) strcpy(dest, src);

src/locale/strxfrm_l.c

@@ -1,6 +1,6 @@
 #include <string.h>
 
-size_t strxfrm_l(char *dest, const char *src, size_t n, locale_t l)
+size_t strxfrm_l(char *restrict dest, const char *restrict src, size_t n, locale_t l)
 {
 	return strxfrm(dest, src, n);
 }

src/locale/wcsxfrm.c

@@ -1,7 +1,7 @@
 #include <wchar.h>
 
 /* collate only by code points */
-size_t wcsxfrm(wchar_t *dest, const wchar_t *src, size_t n)
+size_t wcsxfrm(wchar_t *restrict dest, const wchar_t *restrict src, size_t n)
 {
 	size_t l = wcslen(src);
 	if (l >= n) {

src/locale/wcsxfrm_l.c

@@ -1,6 +1,6 @@
 #include <wchar.h>
 
-size_t wcsxfrm_l(wchar_t *dest, const wchar_t *src, size_t n, locale_t locale)
+size_t wcsxfrm_l(wchar_t *restrict dest, const wchar_t *restrict src, size_t n, locale_t locale)
 {
 	return wcsxfrm(dest, src, n);
 }