internal/rosa: GNU make artifact

This compiles GNU make from source. This is unfortunately required by many programs, but is a cure dependency only.

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

internal/rosa/rosa.go

@@ -36,6 +36,9 @@ func mustDecode(s string) pkg.Checksum {
 }
 
 var (
+	// AbsUsrSrc is the conventional directory to place source code under.
+	AbsUsrSrc = fhs.AbsUsr.Append("src")
+
 	// AbsSystem is the Rosa OS installation prefix.
 	AbsSystem = fhs.AbsRoot.Append("system")
 )