internal/rosa: migrate GNU software

These are quite trivial, so migrate them in one pass.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/python.go

@@ -150,7 +150,7 @@ func (*PipHelper) createDir() bool { return false }
 func (*PipHelper) wantsDir() string { return `"$(mktemp -d)"` }
 
 // script generates the pip3 install command.
-func (attr *PipHelper) script(_ *S, name string) string {
+func (attr *PipHelper) script(_ Toolchain, name string) string {
 	if attr == nil {
 		attr = new(PipHelper)
 	}