runtime: stack growth adjustments, cleanup
	* keep coherent SP/PC in gobuf
	  (i.e., SP that would be in use at that PC)
	* gogocall replaces setspgoto,
	  should work better in presence of link registers
	* delete unused system calls

only amd64; 386 is now broken

R=r
DELTA=548  (183 added, 183 deleted, 182 changed)
OCL=30381
CL=30442
diff --git a/src/pkg/runtime/Makefile b/src/pkg/runtime/Makefile
index cd0bdaa..498bf0b 100644
--- a/src/pkg/runtime/Makefile
+++ b/src/pkg/runtime/Makefile
@@ -75,6 +75,7 @@
 	runtime.h\
 	hashmap.h\
 	malloc.h\
+	$(GOARCH)/asm.h\
 	$(GOOS)/os.h\
 	$(GOOS)/$(GOARCH)/defs.h\