string: move header to standard location

Anything that implements POSIX should also be where POSIX defines
it to be, otherwise it would be pretty useless lol

arch/at91sam3x8e/sched.c

@@ -6,9 +6,10 @@
 #include <arch/at91sam3x8e/interrupt.h>
 
 #include <ardix/atomic.h>
-#include <ardix/string.h>
 #include <ardix/sched.h>
 
+#include <string.h>
+
 extern struct task *_sched_current_task;
 
 void irq_sys_tick(void)

arch/at91sam3x8e/serial.c

@@ -7,7 +7,6 @@
 #include <ardix/malloc.h>
 #include <ardix/ringbuf.h>
 #include <ardix/serial.h>
-#include <ardix/string.h>
 #include <ardix/types.h>
 
 #include <arch/at91sam3x8e/hardware.h>
@@ -16,6 +15,7 @@
 
 #include <errno.h>
 #include <stddef.h>
+#include <string.h>
 
 struct arch_serial_device arch_serial_default_device = {
 	.tx_current = NULL,

arch/at91sam3x8e/startup.c

@@ -5,10 +5,10 @@
 #include <arch/at91sam3x8e/interrupt.h>
 
 #include <ardix/malloc.h>
-#include <ardix/string.h>
 
 #include <stddef.h>
 #include <stdint.h>
+#include <string.h>
 #include <toolchain.h>
 
 /* from flash.ld */

arch/at91sam3x8e/sys.c

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 /* See the end of this file for copyright, license, and warranty information. */
 
-#include <stddef.h>
-#include <stdint.h>
 #include <arch/at91sam3x8e/interrupt.h>
 #include <arch/hardware.h>
-#include <ardix/string.h>
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
 #include <toolchain.h>
 
 /*

kernel/printk.c

@@ -1,16 +1,15 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 /* See the end of this file for copyright, license, and warranty information. */
 
+#include <ardix/printk.h>
+#include <ardix/serial.h>
+
 #include <errno.h>
 /* Using GCC's stdarg.h is recommended even with -nodefaultlibs and -fno-builtin */
 #include <stdarg.h>
 #include <stddef.h>
 #include <stdint.h>
-
-#include <ardix/printk.h>
-#include <ardix/serial.h>
-#include <ardix/string.h>
-
+#include <string.h>
 #include <toolchain.h>
 
 /*

kernel/sched.c

@@ -7,11 +7,11 @@
 #include <ardix/atomic.h>
 #include <ardix/malloc.h>
 #include <ardix/sched.h>
-#include <ardix/string.h>
 #include <ardix/types.h>
 
 #include <errno.h>
 #include <stddef.h>
+#include <string.h>
 
 extern uint32_t _sstack;
 extern uint32_t _estack;
@@ -84,6 +84,36 @@ void *sched_process_switch(void *curr_sp)
 	return _sched_current_task->sp;
 }
 
+struct task *sched_fork(struct task *parent)
+{
+	pid_t pid;
+	struct task *child = malloc(sizeof(*child));
+
+	if (child == NULL)
+		goto err_alloc;
+
+	for (pid = 0; pid < CONFIG_SCHED_MAXTASK; pid++) {
+		if (_sched_tasktab[pid] == NULL)
+			break;
+	}
+	if (pid == CONFIG_SCHED_MAXTASK)
+		goto err_maxtask;
+
+	child->pid = pid;
+	list_init(&child->children);
+	list_insert(&parent->children, &child->siblings);
+
+err_maxtask:
+	free(child);
+err_alloc:
+	return NULL;
+}
+
+struct task *sched_current_task(void)
+{
+	return _sched_current_task;
+}
+
 /*
  * This file is part of Ardix.
  * Copyright (c) 2020, 2021 Felix Kopp <owo@fef.moe>.

kernel/userspace.c

@@ -4,7 +4,7 @@
 #include <ardix/types.h>
 #include <ardix/userspace.h>
 
-#include <ardix/string.h>
+#include <string.h>
 #include <toolchain.h>
 
 /*

lib/malloc.c

@@ -4,9 +4,9 @@
 #include <ardix/atomic.h>
 #include <ardix/list.h>
 #include <ardix/malloc.h>
-#include <ardix/string.h>
 #include <ardix/types.h>
 
+#include <string.h>
 #include <toolchain.h>
 
 /*

lib/string.c

@@ -1,11 +1,11 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 /* See the end of this file for copyright, license, and warranty information. */
 
-#include <ardix/string.h>
 #include <ardix/types.h>
 
-#include <toolchain.h>
 #include <stdbool.h>
+#include <string.h>
+#include <toolchain.h>
 
 #ifndef __HAVE_ASM_MEMCMP
 int memcmp(const void *s1, const void *s2, size_t n)