add or1k (OpenRISC 1000) architecture port

With the exception of a fenv implementation, the port is fully featured.
The port has been tested in or1ksim, the golden reference functional
simulator for OpenRISC 1000.
It passes all libc-test tests (except the math tests that
requires a fenv implementation).

The port assumes an or1k implementation that has support for
atomic instructions (l.lwa/l.swa).

Although it passes all the libc-test tests, the port is still
in an experimental state, and has yet experienced very little
'real-world' use.

crt/or1k/crti.s

@@ -0,0 +1,11 @@
+.section .init
+.global _init
+_init:
+	l.addi	r1,r1,-4
+	l.sw	0(r1),r9
+
+.section .fini
+.global _fini
+_fini:
+	l.addi  r1,r1,-4
+	l.sw    0(r1),r9

crt/or1k/crtn.s

@@ -0,0 +1,9 @@
+.section .init
+	l.lwz	r9,0(r1)
+	l.jr	r9
+	 l.addi	r1,r1,4
+
+.section .fini
+	l.lwz	r9,0(r1)
+	l.jr	r9
+	 l.addi	r1,r1,4