Add support for ARM

- Build system fixes
- No user-mode high-precision timer by default, use clock_gettime
- Use C11 aligned_alloc pending C++17 std::aligned_alloc

Change-Id: I268365bdfd11d1e817a89584b9e086ee5b86e1dc

runtime/cmake_modules/hsa_common.cmake

@@ -57,9 +57,9 @@ if(UNIX)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fpic")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wl,--unresolved-symbols=ignore-in-shared-libs")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-strict-aliasing")
-  if ( IS64BIT )
+  if ( CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" )
     set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m64  -msse -msse2" )
-  else ()
+  elseif ( CMAKE_SYSTEM_PROCESSOR STREQUAL "x86" )
     set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m32" )
   endif ()
   if ( "${CMAKE_BUILD_TYPE}" STREQUAL Debug )