[gnome-builder] make: check for text/x-makefile content-type

[Christian Hergert <chergert src gnome org>]

commit 5c1b61636b59d98b06716ec537c0c3dd5e7d94d7
Author: Christian Hergert <chergert redhat com>
Date:   Tue Jun 4 18:29:56 2019 -0700

    make: check for text/x-makefile content-type

 src/plugins/make/make.plugin | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/plugins/make/make.plugin b/src/plugins/make/make.plugin
index 7e7b66e86..8c15569e6 100644
--- a/src/plugins/make/make.plugin
+++ b/src/plugins/make/make.plugin
@@ -11,4 +11,5 @@ Name=Make
 X-Has-Resources=true
 X-Project-File-Filter-Name=Makefile Project
 X-Project-File-Filter-Pattern=Makefile
+X-Project-File-Filter-Content-Type=text/x-makefile
 X-Builder-ABI=@PACKAGE_ABI@