os: implement StartProcess

Signed-off-by: leongross <leon.gross@9elements.com>

builder/musl.go

@@ -136,12 +136,20 @@ var libMusl = Library{
 			"thread/*.c",
 			"time/*.c",
 			"unistd/*.c",
+			"process/*.c",
 		}
+
 		if arch == "arm" {
 			// These files need to be added to the start for some reason.
 			globs = append([]string{"thread/arm/*.c"}, globs...)
 		}
 
+		if arch != "aarch64" && arch != "mips" {
+			//aarch64 and mips have no architecture specific code, either they
+			// are not supported or don't need any?
+			globs = append([]string{"process/" + arch + "/*.s"}, globs...)
+		}
+
 		var sources []string
 		seenSources := map[string]struct{}{}
 		basepath := goenv.Get("TINYGOROOT") + "/lib/musl/src/"