Fix dosbox build on glibc
Fix dosbox build on glibc

off_t is defined in sys/types.h

TEST=NACL_GLIBC=1 make dosbox
Review URL: https://chromiumcodereview.appspot.com/10878044

git-svn-id: 84b3587ce119b778414dcb50e18b7479aacf4f1d@634 7dad1e8b-422e-d2af-fbf5-8013b78bd812

dtkav/naclports,kuscsik/naclports,kosyak/naclports_samsung-smart-tv,adlr/naclports,Schibum/naclports,kuscsik/naclports,clchiou/naclports,Schibum/naclports,clchiou/naclports,binji/naclports,adlr/naclports,kosyak/naclports_samsung-smart-tv,dtkav/naclports,kuscsik/naclports,yeyus/naclports,kosyak/naclports_samsung-smart-tv,Schibum/naclports,kosyak/naclports_samsung-smart-tv,adlr/naclports,binji/naclports,kosyak/naclports_samsung-smart-tv,clchiou/naclports,kuscsik/naclports,yeyus/naclports,yeyus/naclports,Schibum/naclports,clchiou/naclports,adlr/naclports,Schibum/naclports,kuscsik/naclports,Schibum/naclports,adlr/naclports,binji/naclports,dtkav/naclports,yeyus/naclports,clchiou/naclports,yeyus/naclports,binji/naclports,dtkav/naclports,yeyus/naclports,dtkav/naclports,binji/naclports