Comment typos.

src/base/ftstream.c

@@ -830,7 +830,7 @@
         goto Exit;
       }
 
-      /* now, compute the signed value is necessary */
+      /* now, compute the signed value if necessary */
       if ( fields->value & FT_FRAME_OP_SIGNED )
         value = (FT_ULong)( (FT_Int32)( value << sign_shift ) >> sign_shift );
 

src/truetype/ttgload.c

@@ -2313,7 +2313,7 @@
        *
        * 1) we have a `tricky' font that heavily relies on the interpreter to
        *    render glyphs correctly, for example DFKai-SB, or
-       * 2) FT_RENDER_MODE_MONO (i.e, monochome rendering) is requested.
+       * 2) FT_RENDER_MODE_MONO (i.e, monochrome rendering) is requested.
        *
        * In those cases, backward compatibility needs to be turned off to get
        * correct rendering.  The rendering is then completely up to the