[smooth] Remove compiler warnings.

* src/smooth/ftgrays.c (gray_convert_glyph): Fix reports from clang.

ChangeLog

@@ -1,3 +1,9 @@
+2016-06-20  Werner Lemberg  <wl@gnu.org>
+
+	[smooth] Remove compiler warnings.
+
+	* src/smooth/ftgrays.c (gray_convert_glyph): Fix reports from clang.
+
 2016-06-20  Alexei Podtelezhnikov  <apodtele@gmail.com>
 
 	[smooth] Sanitize memory managenent.

src/smooth/ftgrays.c

@@ -1940,21 +1940,21 @@ typedef ptrdiff_t  FT_PtrDist;
 
         /* memory management */
         {
-          int    ycount = band->max - band->min;
-          int    cell_start;
+          unsigned long  ycount = (unsigned long)( band->max - band->min );
+          unsigned long  cell_start;
 
 
-          cell_start = ( ycount * sizeof( PCell ) + sizeof( TCell ) - 1 ) /
-                       sizeof( TCell );
+          cell_start = ( ycount * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) /
+                       sizeof ( TCell );
 
           if ( FT_MAX_GRAY_POOL - cell_start < 2 )
             goto ReduceBands;
 
           ras.cells     = (PCell)ras.buffer + cell_start;
-          ras.max_cells = FT_MAX_GRAY_POOL - cell_start;
+          ras.max_cells = (FT_PtrDist)( FT_MAX_GRAY_POOL - cell_start );
 
           ras.ycells = (PCell*)ras.buffer;
-          ras.ycount = ycount;
+          ras.ycount = (TPos)ycount;
           while ( ycount )
             ras.ycells[--ycount] = NULL;
         }