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

fusl/include/setjmp.h

Index: fusl/include/setjmp.h
diff --git a/fusl/include/setjmp.h b/fusl/include/setjmp.h
new file mode 100644
index 0000000000000000000000000000000000000000..2d43abf84f54ad9fc9501e0204816579c9b0de99
--- /dev/null
+++ b/fusl/include/setjmp.h
@@ -0,0 +1,41 @@
+#ifndef	_SETJMP_H
+#define	_SETJMP_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <features.h>
+
+#include <bits/setjmp.h>
+
+typedef struct __jmp_buf_tag {
+	__jmp_buf __jb;
+	unsigned long __fl;
+	unsigned long __ss[128/sizeof(long)];
+} jmp_buf[1];
+
+#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
+ || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
+ || defined(_BSD_SOURCE)
+typedef jmp_buf sigjmp_buf;
+int sigsetjmp (sigjmp_buf, int);
+_Noreturn void siglongjmp (sigjmp_buf, int);
+#endif
+
+#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
+ || defined(_BSD_SOURCE)
+int _setjmp (jmp_buf);
+_Noreturn void _longjmp (jmp_buf, int);
+#endif
+
+int setjmp (jmp_buf);
+_Noreturn void longjmp (jmp_buf, int);
+
+#define setjmp setjmp
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif