Default to using hard tabs in Makefile files

This is a temporary solution until scoped settings supports this
type of restriction.

Closes atom/language-make#3

spec/text-editor-spec.coffee

@@ -3470,6 +3470,19 @@ describe "TextEditor", ->
       runs ->
         expect(editor.softTabs).toBe false
 
+    it "uses hard tabs in Makefile files", ->
+      # FIXME remove once this is handled by a scoped setting in the
+      # language-make package
+
+      waitsForPromise ->
+        atom.packages.activatePackage('language-make')
+
+      waitsForPromise ->
+        atom.project.open('Makefile').then (o) -> editor = o
+
+      runs ->
+        expect(editor.softTabs).toBe false
+
   describe ".destroy()", ->
     it "destroys all markers associated with the edit session", ->
       expect(buffer.getMarkerCount()).toBeGreaterThan 0

src/text-editor.coffee

@@ -2243,6 +2243,10 @@ class TextEditor extends Model
   # Returns a {Boolean} or undefined if no non-comment lines had leading
   # whitespace.
   usesSoftTabs: ->
+    # FIXME Remove once this can be specified as a scoped setting in the
+    # language-make package
+    return false if @getGrammar().scopeName is 'source.makefile'
+
     for bufferRow in [0..@buffer.getLastRow()]
       continue if @displayBuffer.tokenizedBuffer.tokenizedLineForRow(bufferRow).isComment()