set CMAKE_SYSTEM_PROCESSOR to x86

CMakeLists.txt

@@ -106,6 +106,7 @@ else(WIN32)
 		)
 		option(BUILD_32BIT "Force building as 32-bit binary")
 		if(BUILD_32BIT)
+			set(CMAKE_SYSTEM_PROCESSOR "x86" CACHE STRING "system processor")
 			set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m32" CACHE STRING "c++ flags")
 			set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -m32" CACHE STRING "c flags")
 		endif(BUILD_32BIT)