Support for cross compilation.

Refactor architecture specific files into arm and x86 name spaces. Make
assemblers and calling conventions use the factory pattern and an
instruction set specifier.

Change-Id: I20cd7aecacc1ae3d418221d98bbe1d69be9162a7
diff --git a/src/constants_arm.h b/src/constants_arm.h
index 2d2acb7..097c6bc 100644
--- a/src/constants_arm.h
+++ b/src/constants_arm.h
@@ -10,6 +10,7 @@
 #include "logging.h"
 
 namespace art {
+namespace arm {
 
 // Defines constants and accessor classes to assemble, disassemble and
 // simulate ARM instructions.
@@ -548,6 +549,7 @@
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
 };
 
+}  // namespace arm
 }  // namespace art
 
 #endif  // ART_SRC_CONSTANTS_ARM_H_