Avoid a circularity; pmichaud++ for noticing.
Add some documentation about signature argument to pirop_mapper.
Store REPR data offset in STables data also.

This makes it much easier for anything that wants to try and work out
sizing/layout before deserializing objects.
Add nqp::x_posixerrno
Add test for nqp::x_posixerrno and pir::const::POSIX_*
Add script to generate list of errno value macros
Generate nqp_const.pir as dependency for building NQP
Include nqp_const.pir in registered constants
Ignore generated nqp_const.pir file
Merge pull request #86 from hoelzro/master

Expose errno and POSIX errno values to NQP
Install nqp_const.pir.
[docs/release_guide.pod] formatting fix
bump VERSION to 2013.03
[docs/release_guide.pod] fix upload instructions
when encountering an error during compilation, show the source text if available
Merge branch 'master' into vmarray-list
Fix a braino in HLL/Compiler.pm. Can't flatten a list into an op call.