Colin Watson: libpipeline 1.2.1 released

I've released libpipeline 1.2.1, and uploaded it to Debian unstable. This is a bug-fix release:

• Retry reads and writes on EINTR.
• Fix opening of output files requested by pipeline_want_outfile; these are now created if they do not already exist, and truncated if they do.
• <pipeline.h> is now wrapped in extern "C" when used in a C++ compilation unit.