 The png library avoids typedef conflicts by altruistically
   appending "png_" to the type names.  Following that approach,
   Leptonica appends "l_" to the type name.  This should avoid
   just about all conflicts.  In the highly unlikely event that it doesn't,
   here's a simple way to change the type declarations throughout
   the Leptonica code:
    (1) customize a file "converttypes.sed" with the following lines:
        /l_uint8/s//YOUR_UINT8_NAME/g
        /l_int8/s//YOUR_INT8_NAME/g
        /l_uint