build rofl: Use x86_64-unknown-linux-musl target

In order to be compatible with alpine linux builds we use in
our containers, the target needs to be built for musl instead
of gnu.

cmd/rofl/build.go

@@ -106,7 +106,7 @@ var (
 
 			// First build for the default target.
 			fmt.Println("Building ELF binary...")
-			elfPath, err := cargo.Build(true, "x86_64-unknown-linux-gnu", features)
+			elfPath, err := cargo.Build(true, "x86_64-unknown-linux-musl", features)
 			if err != nil {
 				cobra.CheckErr(fmt.Errorf("failed to build ELF binary: %w", err))
 			}