Log Message:
Update fox to 1.6.57.

This supersedes the 1.6.56 update from PR pkg/52967.

April 3 - FOX STABLE 1.6.57

    Libtool flags added on behalf of FXRuby builds and missing UNICODE flag
    added for CYGWIN32 build.

January 16 - FOX STABLE 1.6.56

    Problem fixed in FXString vformat().

July 19 - FOX STABLE 1.6.55

    Fix FXMemoryStream position() API: error code was set moving stream
    position to end of buffer.

April 20 - FOX STABLE 1.6.54

    Fix core dump using old GNU C Library or CYGWIN inside
    FXString::vformat.cpp.

December 3 - FOX STABLE 1.6.53

    Fixed typo in FXString::vformat.cpp.

March 15 - FOX STABLE 1.6.51

    Small fixes for 64-bit casts in dctest.cpp (compiler warning issues).
    JPEG image I/O color spaces handled better.
    FXApp input callback message ID for SEL_IO_EXCEPT was wrong.
    Change in how FXStat determines if a file is an executable (Windows).