From: Jeff Mahoney <jeffm@suse.com>
Subject: magefile: use stable timestamps for build

In order to create reprodicible builds, we can't have timestamps that vary
without anything else changing.
diff --git a/magefile.go b/magefile.go
index 16badc2b..76011657 100644
--- a/magefile.go
+++ b/magefile.go
@@ -428,10 +428,18 @@ func build_gui_files() error {
 }
 
 func flags() string {
-	timestamp := time.Now().Format(time.RFC3339)
+	timestamp := os.Getenv("VELOCIRAPTOR_BUILD_TIME")
+	if timestamp == "" {
+		timestamp = time.Now().Format(time.RFC3339)
+	}
 	flags := fmt.Sprintf(` -X "www.velocidex.com/golang/velociraptor/config.build_time=%s"`, timestamp)
 
-	flags += fmt.Sprintf(` -X "www.velocidex.com/golang/velociraptor/config.commit_hash=%s"`, hash())
+	head := os.Getenv("VELOCIRAPTOR_GIT_HEAD")
+	if head == "" {
+		head = hash()
+	}
+
+	flags += fmt.Sprintf(` -X "www.velocidex.com/golang/velociraptor/config.commit_hash=%s"`, head)
 
 	// If we are running on the CI pipeline we need to know the run
 	// number and URL so we can report them.