Changes in version 1.21:

Detection of forbidden combinations of characters in trailing data has been
improved.

Errors are now also checked when closing the input file.

Lzip now compiles on DOS with DJGPP. (Patch from Robert Riebisch).

The descriptions of '-0..-9', '-m' and '-s' in the manual have been
improved.

The configure script now accepts appending options to CXXFLAGS using the
syntax 'CXXFLAGS+=OPTIONS'.

It has been documented in INSTALL the use of
CXXFLAGS+='-D __USE_MINGW_ANSI_STDIO' when compiling on MinGW.
