pbzip2-2 boost/std port: progress indicator doesn't display "%"

[Yavor Nikolov]

Progress indicator doesn't display '%' character (just the number) when compiled on Solaris with Sun Studio 12.1.

Escaping % (i.e. "\%..." instead of "%...") seems to resolve the issue.

[Yavor Nikolov (yavor-nikolov)]

"\%..." is also not a good idea since is considered anachronism. It's better to use "%%..." instead which is in fact the format which has been used in 1.x.x.

[Yavor Nikolov (yavor-nikolov)]

Since seems compilers sometimes behave differently on interpreting format specifiers and % - instead of escaping % maybe it would be better to just replace fprintf with std::fputs.
Formatting is not needed anyway in the particular case; fputs is simpler and behaves more consistently within the different compilers. I just tested that on Solaris and it works fine.