diff --git a/src/bgl.cc b/src/bgl.cc
index 22a6cba8..92a6ff55 100644
--- a/src/bgl.cc
+++ b/src/bgl.cc
@@ -86,6 +86,26 @@ namespace
     return in;
   }
 
+  // Since the standard isspace() is locale-specific, we need something
+  // that would never mess up our utf8 input. The stock one worked fine under
+  // Linux but was messing up strings under Windows.
+  bool isspace_c( int c )
+  {
+    switch( c )
+    {
+      case ' ':
+      case '\f':
+      case '\n':
+      case '\r':
+      case '\t':
+      case '\v':
+        return true;
+
+      default:
+        return false;
+    }
+  }
+
   // Removes any leading or trailing whitespace
   void trimWs( string & word )
   {
@@ -93,7 +113,7 @@ namespace
     {
       unsigned begin = 0;
 
-      while( begin < word.size() && isspace( word[ begin ] ) )
+      while( begin < word.size() && isspace_c( word[ begin ] ) )
         ++begin;
 
       if ( begin == word.size() ) // Consists of ws entirely?
@@ -104,7 +124,7 @@ namespace
 
         // Doesn't consist of ws entirely, so must end with just isspace()
         // condition.
-        while( isspace( word[ end - 1 ] ) )
+        while( isspace_c( word[ end - 1 ] ) )
           --end;
 
         if ( end != word.size() || begin )