Delete output files before copying to them.

Avoid ETXTBSY when copying over a file that's being executed.

Test: manual
Test: m -j
Change-Id: I0427b5018e67e12f685bce95028831b5661eee2c

android/defs.go

@@ -47,7 +47,7 @@ var (
 	// A copy rule.
 	Cp = pctx.AndroidStaticRule("Cp",
 		blueprint.RuleParams{
-			Command:     "cp $cpPreserveSymlinks $cpFlags $in $out",
+			Command:     "rm -f $out && cp $cpPreserveSymlinks $cpFlags $in $out",
 			Description: "cp $out",
 		},
 		"cpFlags")