Makefile.vc: rule maintenance
Makefile.vc: rule maintenance

Remove the bulk of xcopys from the TARGET rule as things are built to
the correct location.
Allow the clean rule to be appended and only delete DLLINC for dll
builds to avoid prompting by erase when it's undefined.

Change-Id: If88b2c68090099777b8be9f3a5fbde2c25ed66a6

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