src: Fixed integer conversion warning on HPUX.
src: Fixed integer conversion warning on HPUX.

This fixes cmockery issue #10.

Signed-off-by: Andreas Schneider <5be00ddc76278cf6077f5047ca3384a88460c671@cryptomilk.org>

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