Fix build flags.
Fix build flags.

tgdavies/codeworld,xwysp/codeworld,xwysp/codeworld,venkat24/codeworld,stefan-j/codeworld,tgdavies/codeworld,pranjaltale16/codeworld,stefan-j/codeworld,parvmor/codeworld,nomeata/codeworld,three/codeworld,d191562687/codeworld,Ye-Yong-Chi/codeworld,d191562687/codeworld,nomeata/codeworld,d191562687/codeworld,stefan-j/codeworld,parvmor/codeworld,google/codeworld,venkat24/codeworld,tgdavies/codeworld,Ye-Yong-Chi/codeworld,xwysp/codeworld,pranjaltale16/codeworld,google/codeworld,venkat24/codeworld,alphalambda/codeworld,Ye-Yong-Chi/codeworld,alphalambda/codeworld,google/codeworld,parvmor/codeworld,three/codeworld,pranjaltale16/codeworld,alphalambda/codeworld,three/codeworld,nomeata/codeworld