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

fusl/arch/or1k/pthread_arch.h

Index: fusl/arch/or1k/pthread_arch.h
diff --git a/fusl/arch/or1k/pthread_arch.h b/fusl/arch/or1k/pthread_arch.h
new file mode 100644
index 0000000000000000000000000000000000000000..7decd769a8598ab35de5293ccc2bf58b51a3c414
--- /dev/null
+++ b/fusl/arch/or1k/pthread_arch.h
@@ -0,0 +1,17 @@
+/* or1k use variant I, but with the twist that tp points to the end of TCB */
+static inline struct pthread *__pthread_self()
+{
+#ifdef __clang__
+	char *tp;
+	__asm__ __volatile__ ("l.ori %0, r10, 0" : "=r" (tp) );
+#else
+	register char *tp __asm__("r10");
+	__asm__ __volatile__ ("" : "=r" (tp) );
+#endif
+	return (struct pthread *) (tp - sizeof(struct pthread));
+}
+
+#define TLS_ABOVE_TP
+#define TP_ADJ(p) ((char *)(p) + sizeof(struct pthread))
+
+#define MC_PC regs.pc