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/process/posix_spawn.c

@@ -8,11 +8,11 @@
 
 extern char **environ;
 
-int __posix_spawnx(pid_t *res, const char *path,
+int __posix_spawnx(pid_t *restrict res, const char *restrict path,
 	int (*exec)(const char *, char *const *),
 	const posix_spawn_file_actions_t *fa,
-	const posix_spawnattr_t *attr,
-	char *const argv[], char *const envp[])
+	const posix_spawnattr_t *restrict attr,
+	char *const argv[restrict], char *const envp[restrict])
 {
 	pid_t pid;
 	sigset_t oldmask;
@@ -89,10 +89,10 @@ int __posix_spawnx(pid_t *res, const char *path,
 	return 0;
 }
 
-int posix_spawn(pid_t *res, const char *path,
+int posix_spawn(pid_t *restrict res, const char *restrict path,
 	const posix_spawn_file_actions_t *fa,
-	const posix_spawnattr_t *attr,
-	char *const argv[], char *const envp[])
+	const posix_spawnattr_t *restrict attr,
+	char *const argv[restrict], char *const envp[restrict])
 {
 	return __posix_spawnx(res, path, execv, fa, attr, argv, envp);
 }

src/process/posix_spawn_file_actions_addopen.c

@@ -4,7 +4,7 @@
 #include <errno.h>
 #include "fdop.h"
 
-int posix_spawn_file_actions_addopen(posix_spawn_file_actions_t *fa, int fd, const char *path, int flags, mode_t mode)
+int posix_spawn_file_actions_addopen(posix_spawn_file_actions_t *restrict fa, int fd, const char *restrict path, int flags, mode_t mode)
 {
 	struct fdop *op = malloc(sizeof *op + strlen(path) + 1);
 	if (!op) return ENOMEM;

src/process/posix_spawnattr_getflags.c

@@ -1,6 +1,6 @@
 #include <spawn.h>
 
-int posix_spawnattr_getflags(const posix_spawnattr_t *attr, short *flags)
+int posix_spawnattr_getflags(const posix_spawnattr_t *restrict attr, short *restrict flags)
 {
 	*flags = attr->__flags;
 	return 0;

src/process/posix_spawnattr_getpgroup.c

@@ -1,6 +1,6 @@
 #include <spawn.h>
 
-int posix_spawnattr_getpgroup(const posix_spawnattr_t *attr, pid_t *pgrp)
+int posix_spawnattr_getpgroup(const posix_spawnattr_t *restrict attr, pid_t *restrict pgrp)
 {
 	*pgrp = attr->__pgrp;
 	return 0;

src/process/posix_spawnattr_getsigdefault.c

@@ -1,6 +1,6 @@
 #include <spawn.h>
 
-int posix_spawnattr_getsigdefault(const posix_spawnattr_t *attr, sigset_t *def)
+int posix_spawnattr_getsigdefault(const posix_spawnattr_t *restrict attr, sigset_t *restrict def)
 {
 	*def = attr->__def;
 	return 0;

src/process/posix_spawnattr_getsigmask.c

@@ -1,6 +1,6 @@
 #include <spawn.h>
 
-int posix_spawnattr_getsigmask(const posix_spawnattr_t *attr, sigset_t *mask)
+int posix_spawnattr_getsigmask(const posix_spawnattr_t *restrict attr, sigset_t *restrict mask)
 {
 	*mask = attr->__mask;
 	return 0;

src/process/posix_spawnattr_setsigdefault.c

@@ -1,6 +1,6 @@
 #include <spawn.h>
 
-int posix_spawnattr_setsigdefault(posix_spawnattr_t *attr, const sigset_t *def)
+int posix_spawnattr_setsigdefault(posix_spawnattr_t *restrict attr, const sigset_t *restrict def)
 {
 	attr->__def = *def;
 	return 0;

src/process/posix_spawnattr_setsigmask.c

@@ -1,6 +1,6 @@
 #include <spawn.h>
 
-int posix_spawnattr_setsigmask(posix_spawnattr_t *attr, const sigset_t *mask)
+int posix_spawnattr_setsigmask(posix_spawnattr_t *restrict attr, const sigset_t *restrict mask)
 {
 	attr->__mask = *mask;
 	return 0;

src/process/posix_spawnp.c

@@ -1,15 +1,15 @@
 #include <spawn.h>
 #include <unistd.h>
 
-int __posix_spawnx(pid_t *, const char *,
+int __posix_spawnx(pid_t *restrict, const char *restrict,
 	int (*)(const char *, char *const *),
 	const posix_spawn_file_actions_t *,
-	const posix_spawnattr_t *, char *const [], char *const []);
+	const posix_spawnattr_t *restrict, char *const *restrict, char *const *restrict);
 
-int posix_spawnp(pid_t *res, const char *file,
+int posix_spawnp(pid_t *restrict res, const char *restrict file,
 	const posix_spawn_file_actions_t *fa,
-	const posix_spawnattr_t *attr,
-	char *const argv[], char *const envp[])
+	const posix_spawnattr_t *restrict attr,
+	char *const argv[restrict], char *const envp[restrict])
 {
 	return __posix_spawnx(res, file, execvp, fa, attr, argv, envp);
 }