Fix MACHINE macro defintion

Fix the detecting whether -fPIC compiler flag is needed or not

CMakeLists.txt

@@ -69,11 +69,7 @@ ELSEIF(${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
 ENDIF()
 
 # Get processor type, sets MACHINE macro
-IF(NOT WIN32)
-	execute_process(COMMAND uname -m
-	    OUTPUT_VARIABLE MACHINE_OUTPUT OUTPUT_STRIP_TRAILING_WHITESPACE)
-	SET(MACHINE ${MACHINE_OUTPUT})
-ENDIF()
+SET(MACHINE ${CMAKE_SYSTEM_PROCESSOR})
 
 SET(EXT_LIB_SWIG_RUBY_MODULAR ".so")
 if(DARWIN)
@@ -120,7 +116,7 @@ SET(CMAKE_C_FLAGS_DISTRIBUTION "-O2")
 SET(CMAKE_CXX_FLAGS_DISTRIBUTION "-O2")
 
 # add fPIC flag
-IF("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+IF("${MACHINE}" STREQUAL "x86_64" OR "${MACHINE}" STREQUAL "amd64")
 	SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
 	SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC")
 	SET(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -fPIC")