Perl: handling of allocation errors. Previously, allocation errors in nginx.xs were more or less ignored, potentially resulting in incorrect code execution in specific low-memory conditions. This is changed to use ctx->error bit and croak(), similarly to how output errors are now handled. Note that this is mostly a cosmetic change, as Perl itself exits on memory allocation errors, and hence nginx with Perl is hardly usable in low-memory conditions.

au BufRead,BufNewFile *.nginx set ft=nginx
au BufRead,BufNewFile */etc/nginx/* set ft=nginx
au BufRead,BufNewFile */usr/local/nginx/conf/* set ft=nginx
au BufRead,BufNewFile nginx.conf set ft=nginx