makefile.unix: clean up libgif2webp_util.a
makefile.unix: clean up libgif2webp_util.a

Change-Id: Iee8650ce91f65f2db568926773d44441633459f3

matanbs/webm.libwebp,PKRoma/libwebp,imazen/libwebp,Maria1099/webm.libwebp,Suvarna1488/webm.libwebp,jiehu5114/libwebp,webmproject/libwebp,iniwf/webm.libwebp,Acidburn0zzz/webm.libwebp,ya7lelkom/libwebp,matanbs/webm.libwebp,rxl194/libwebp,rxl194/libwebp,reimaginemedia/webm.libwebp,Acidburn0zzz/webm.libwebp,gshORTON/webm.libwebp,keane83/BLE_IM,jiehu5114/libwebp,ttyangf/libwebp,Maria1099/webm.libwebp,comoyo/gonzo-libwebp,redengineer/libwebp,ttyangf/libwebp,ericmckean/webm.libwebp,Suvarna1488/webm.libwebp,kim42083/webm.libwebp,ericmckean/webm.libwebp,ttyangf/libwebp,keane83/BLE_IM,jiehu5114/libwebp,matanbs/webm.libwebp,reimaginemedia/webm.libwebp,ericmckean/webm.libwebp,abwiz0086/webm.libwebp,webmproject/libwebp,zofuthan/libwebp,zofuthan/libwebp,kim42083/webm.libwebp,imazen/libwebp,imazen/libwebp,reimaginemedia/webm.libwebp,Suvarna1488/webm.libwebp,gshORTON/webm.libwebp,PKRoma/libwebp,matanbs/webm.libwebp,matanbs/webm.libwebp,jacklicn/libwebp,iniwf/webm.libwebp,redengineer/libwebp,ericmckean/webm.libwebp,yohunl/libwebp,keane83/BLE_IM,keane83/BLE_IM,ya7lelkom/libwebp,Suvarna1488/webm.libwebp,webmproject/libwebp,comoyo/gonzo-libwebp,keane83/BLE_IM,altogother/webm.libwebp,appunite/libwebp,Aexyn/libwebp,jacklicn/libwebp,ya7lelkom/libwebp,redengineer/libwebp,redengineer/libwebp,imazen/libwebp,jacklicn/libwebp,altogother/webm.libwebp,gshORTON/webm.libwebp,webmproject/libwebp,PKRoma/libwebp,ttyangf/libwebp,altogother/webm.libwebp,abwiz0086/webm.libwebp,PKRoma/libwebp,comoyo/gonzo-libwebp,abwiz0086/webm.libwebp,zofuthan/libwebp,kleopatra999/webm.libwebp,Aexyn/libwebp,iniwf/webm.libwebp,appunite/libwebp,Acidburn0zzz/webm.libwebp,Aexyn/libwebp,Suvarna1488/webm.libwebp,Maria1099/webm.libwebp,kalli123/webm.libwebp,abwiz0086/webm.libwebp,kalli123/webm.libwebp,jiehu5114/libwebp,PKRoma/libwebp,jacklicn/libwebp,jacklicn/libwebp,yohunl/libwebp,Acidburn0zzz/webm.libwebp,reimaginemedia/webm.libwebp,comoyo/gonzo-libwebp,Aexyn/libwebp,yohunl/libwebp,yohunl/libwebp,comoyo/gonzo-libwebp,kleopatra999/webm.libwebp,Acidburn0zzz/webm.libwebp,ya7lelkom/libwebp,reimaginemedia/webm.libwebp,iniwf/webm.libwebp,kim42083/webm.libwebp,altogother/webm.libwebp,kleopatra999/webm.libwebp,ttyangf/libwebp,kim42083/webm.libwebp,zofuthan/libwebp,comoyo/gonzo-libwebp,imazen/libwebp,appunite/libwebp,Aexyn/libwebp,appunite/libwebp,jiehu5114/libwebp,Maria1099/webm.libwebp,comoyo/gonzo-libwebp,appunite/libwebp,kleopatra999/webm.libwebp,gshORTON/webm.libwebp,rxl194/libwebp,redengineer/libwebp,kleopatra999/webm.libwebp,iniwf/webm.libwebp,kalli123/webm.libwebp,appunite/libwebp,Maria1099/webm.libwebp,ericmckean/webm.libwebp,PKRoma/libwebp,altogother/webm.libwebp,abwiz0086/webm.libwebp,ya7lelkom/libwebp,kim42083/webm.libwebp,rxl194/libwebp,kalli123/webm.libwebp,yohunl/libwebp,zofuthan/libwebp,rxl194/libwebp,gshORTON/webm.libwebp,kalli123/webm.libwebp,webmproject/libwebp