MDL-48328 theme_bootstrapbase: lessc is failing to compile our less.

theme/bootstrapbase/less/bootstrap/mixins.less

@@ -317,9 +317,9 @@
 // Default value is `visible`, but can be changed to `hidden
 // See git pull https://github.com/dannykeane/bootstrap.git backface-visibility for examples
 .backface-visibility(@visibility){
-	-webkit-backface-visibility: @visibility;
-	   -moz-backface-visibility: @visibility;
-	        backface-visibility: @visibility;
+    -webkit-backface-visibility: @visibility;
+       -moz-backface-visibility: @visibility;
+            backface-visibility: @visibility;
 }
 
 // Background clipping
@@ -589,8 +589,8 @@
     .offset (@columns) {
       margin-left: (@gridColumnWidth * @columns) + (@gridGutterWidth * (@columns + 1));
     }
-
     .span (@columns) {
+    // The logic from here was copied to less/bootstrap/navbar.less#L200.
       width: (@gridColumnWidth * @columns) + (@gridGutterWidth * (@columns - 1));
     }
 
@@ -634,7 +634,7 @@
 
     .offset (@columns) {
       margin-left: (@fluidGridColumnWidth * @columns) + (@fluidGridGutterWidth * (@columns - 1)) + (@fluidGridGutterWidth*2);
-  	  *margin-left: (@fluidGridColumnWidth * @columns) + (@fluidGridGutterWidth * (@columns - 1)) - (.5 / @gridRowWidth * 100 * 1%) + (@fluidGridGutterWidth*2) - (.5 / @gridRowWidth * 100 * 1%);
+      *margin-left: (@fluidGridColumnWidth * @columns) + (@fluidGridGutterWidth * (@columns - 1)) - (.5 / @gridRowWidth * 100 * 1%) + (@fluidGridGutterWidth*2) - (.5 / @gridRowWidth * 100 * 1%);
     }
 
     .offsetFirstChild (@columns) {

theme/bootstrapbase/less/bootstrap/navbar.less

@@ -196,7 +196,8 @@
 .navbar-static-top .container,
 .navbar-fixed-top .container,
 .navbar-fixed-bottom .container {
-  #grid > .core > .span(@gridColumns);
+// This is a Moodle hack - please see less/bootstrap/mixins.less#L593.
+  width: (@gridColumnWidth * @gridColumns) + (@gridGutterWidth * (@gridColumns - 1));
 }
 
 // Fixed to top