Workaround SytleBuffer bug.

https://github.com/jamescoxon/dl-fldigi/issues/22 and upstream:
 Invalid data breaking fl_height() and fl_width(). Rare but locally abundant.

src/widgets/Fl_Text_Display_mod.cxx

@@ -318,11 +318,15 @@ void Fl_Text_Display_mod::resize(int X, int Y, int W, int H) {
   text_area.y = Y+TOP_MARGIN;
   text_area.w = W-LEFT_MARGIN-RIGHT_MARGIN;
   text_area.h = H-TOP_MARGIN-BOTTOM_MARGIN;
+#ifdef STYLEBUFFER_CORRUPT_FIX
   int i;
 
   /* Find the new maximum font height for this text display */
   for (i = 0, mMaxsize = fl_height(textfont(), textsize()); i < mNStyles; i++)
     mMaxsize = max(mMaxsize, fl_height(mStyleTable[i].font, mStyleTable[i].size));
+#else
+   mMaxsize = fl_height(textfont(), textsize());
+#endif
 
   // did we have scrollbars initially?
   unsigned int hscrollbarvisible = mHScrollBar->visible();
@@ -2190,7 +2194,8 @@ double Fl_Text_Display_mod::string_width( const char *string, int length, int st
 
   Fl_Font font;
   Fl_Fontsize fsize;
-
+
+#ifdef STYLEBUFFER_CORRUPT_FIX  
   if ( mNStyles && (style & STYLE_LOOKUP_MASK) ) {
     int si = (style & STYLE_LOOKUP_MASK) - 'A';
     if (si < 0) si = 0;
@@ -2202,6 +2207,10 @@ double Fl_Text_Display_mod::string_width( const char *string, int length, int st
     font  = textfont();
     fsize = textsize();
   }
+#else
+  font  = textfont();
+  fsize = textsize();
+#endif
   fl_font( font, fsize );
   return fl_width( string, length );
 }