Add a "fork" of musl as //fusl.

fusl/src/misc/realpath.c

Index: fusl/src/misc/realpath.c
diff --git a/fusl/src/misc/realpath.c b/fusl/src/misc/realpath.c
new file mode 100644
index 0000000000000000000000000000000000000000..88c849cda33de1e285a5b1eec7dfe9c222d013e5
--- /dev/null
+++ b/fusl/src/misc/realpath.c
@@ -0,0 +1,45 @@
+#include <stdlib.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include "syscall.h"
+
+void __procfdname(char *, unsigned);
+
+char *realpath(const char *restrict filename, char *restrict resolved)
+{
+	int fd;
+	ssize_t r;
+	struct stat st1, st2;
+	char buf[15+3*sizeof(int)];
+	char tmp[PATH_MAX];
+
+	if (!filename) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	fd = sys_open(filename, O_PATH|O_NONBLOCK|O_CLOEXEC);
+	if (fd < 0) return 0;
+	__procfdname(buf, fd);
+
+	r = readlink(buf, tmp, sizeof tmp - 1);
+	if (r < 0) goto err;
+	tmp[r] = 0;
+
+	fstat(fd, &st1);
+	r = stat(tmp, &st2);
+	if (r<0 || st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino) {
+		if (!r) errno = ELOOP;
+		goto err;
+	}
+
+	__syscall(SYS_close, fd);
+	return resolved ? strcpy(resolved, tmp) : strdup(tmp);
+err:
+	__syscall(SYS_close, fd);
+	return 0;
+}