include: Correctly detect uintptr_t size on Linux.
include: Correctly detect uintptr_t size on Linux.

This is needed to compile for i686 on a x86_64 system.

VladimirTyrin/cmocka,Odie/cmocka,wingyplus/cmocka,chadversary/cmocka,nuumio/cmocka,jamesmunns/CMocka,wingyplus/cmocka,aleksandr-vin/cmock,JonathonReinhart/cmocka,jamesmunns/CMocka,tyc/cmocka,JonathonReinhart/cmocka,nuumio/cmocka,jhrozek/cmocka,jhrozek/cmocka,tyc/cmocka,linuxmaniac/cmocka,aleksandr-vin/cmock,chadversary/cmocka,jschmidlapp/cmocka,Odie/cmocka,lsjostro/cmocka,dsch/cmocka,clibs/cmocka,lsjostro/cmocka,dsch/cmocka,nuumio/cmocka,clibs/cmocka,jhrozek/cmocka,VladimirTyrin/cmocka,jschmidlapp/cmocka,jschmidlapp/cmocka,tyc/cmocka,Odie/cmocka,linuxmaniac/cmocka