rstudio/rmarkdown — pull request #72 by trestletech (2014-04-24 19:28:35+00:00)
Title: Check for critical environment variables.

Ensure that LANG and HOME are both set before running Pandoc, as their
absence can cause fatal errors as discussed in #31.

I was torn about whether we should fail or take a stab at setting a default LANG. To me, this behavior is the most reasonable.