diff --git a/build/bakefiles/wx.bkl b/build/bakefiles/wx.bkl
index 1265e4dc77..6d6995515a 100644
--- a/build/bakefiles/wx.bkl
+++ b/build/bakefiles/wx.bkl
@@ -87,7 +87,7 @@
 
         <data-files>
             <srcdir>$(SRCDIR)/build/bakefiles/wxpresets/presets</srcdir>
-            <files>wx.bkl wx_unix.bkl wx_win32.bkl wx_xrc.bkl</files>
+            <files>wx.bkl wx_unix.bkl wx_win32.bkl wx_xrc.bkl wx_presets.py</files>
             <install-to>$(DATADIR)/bakefile/presets</install-to>
         </data-files>
 
diff --git a/build/bakefiles/wxpresets/presets/wx.bkl b/build/bakefiles/wxpresets/presets/wx.bkl
index eae18ed220..ff06b7f6fd 100644
--- a/build/bakefiles/wxpresets/presets/wx.bkl
+++ b/build/bakefiles/wxpresets/presets/wx.bkl
@@ -112,6 +112,7 @@
 
     <requires version="0.2.2"/>
 
+    <using module="wx_presets"/>
 
     <!-- this variable identifies the version of the wx presets.
          this is changed only when major changes to wxpresets take place.
@@ -272,8 +273,7 @@
         <if cond="WX_DEBUG=='0' and WX_UNICODE=='1'">u</if>
     </set>
 
-    <!-- FIXME: how to make it a make var? -->
-    <set var="COMPILER_PREFIX">$(COMPILER)</set>
+    <set var="COMPILER_PREFIX" make_var="1">$(COMPILER)</set>
 
 
 
diff --git a/build/bakefiles/wxpresets/presets/wx_presets.py b/build/bakefiles/wxpresets/presets/wx_presets.py
new file mode 100644
index 0000000000..60af474f6c
--- /dev/null
+++ b/build/bakefiles/wxpresets/presets/wx_presets.py
@@ -0,0 +1,11 @@
+
+# We use 'COMPILER_PREFIX' option in places where bakefile doesn't like it, so
+# we must register a substitution function for it that provides additional
+# knowledge about the option (in this case that it does not contain dir
+# separators and so utils.nativePaths() doesn't have to do anything with it):
+
+from utils import addSubstituteCallback
+
+def __noopSubst(name, func, caller):
+    return '$(%s)' % name
+addSubstituteCallback('COMPILER_PREFIX', __noopSubst)