ignore trailing garbage on decompress needed

[Yavor Nikolov]

Add option-controlled functionality to ignore trailing garbage on decompression instead of failing with error.

This is in order to keep compatible with bzip2 and to prevent breaking existing code dealing with Gentoo package format.

[Yavor Nikolov (yavor-nikolov)]

Working but still just barely tested implementation has been pushed to lp:~yavor-nikolov/pbzip2/pbzip2-1.1.x-yn-ignore-trailing.

The feature is switched on/off using following option:
--ignore-trailing-garbage=0 (Old behaviour - trailing garbage causes error and abort)
--ignore-trailing-garbage=1 (Trailing garbage is just ignored /printing just a warning about it if in verbose mode/)
--ignore-trailing-garbage (Same as --ignore-trailing-garbage=1)

The default value flag could be specified by conditional compilation with IGNORE_TRAILING_GARBAGE=<flag value>. (The default is 0).

[Yavor Nikolov (yavor-nikolov)]

An additional suggestion (by Michał) came for the default parameter value:
"switching IgnoreTrailingGarbage on by default if the program is called as 'bzip2', 'bunzip2' or 'bzcat' (i.e. has no 'p' before)"

[Yavor Nikolov (yavor-nikolov)]

A bit clarification about the bug and it's current fix: default behavior is still determined by IGNORE_TRAILING_GARBAGE macro only. (I.e. the Michał's idea to make some adjustments based on program name remained out of scope of this bug. New ones may be opened for further refinement in subsequent releases).

[Yavor Nikolov (yavor-nikolov)]

My last update here to be ignored... The program-name based default has been in fact already implemented as per the description in Makefile:

# Comment out CFLAGS line below to explicity set ignore trailing garbage
# default behavior: 0 - disabled; 1 - enabled (ignore garbage by default)
# If IGNORE_TRAILING_GARBAGE is not defined: behavior is automatically determined
# by program name: bzip2, bunzip2, bzcat - ignore garbage; otherwise - not.
#CFLAGS += -DIGNORE_TRAILING_GARBAGE=1