In case allocating for the file failed, return `NULL`
Don't depend on Lasem's itex2MML wrapper

`lsm_itex_to_mathml` currently uses `int` for `size`, but actually,
`itex2MML_parse` correctly uses `unsigned long`
We don't need these vars actually
And (and check against) `maxsize` of LaTeX string
Merge branch 'master' into a-few-secure-bolts
Switch back to `lsm_itex_to_mathml`

Upstream sizing error has been fixed: lsm_itex_to_mathml
Only call `g_type_init` if it's necessary
Merge master
Fix some typos introduced when merging `master`
Switch to the friendly `gsize` type
Simplify the large string check

`FIX2INT` expects numbers less than `LONG_MAX`, so we do not need to
explicitly check that `latex_size` falls within the range. But, `gsize`
can be greater than `LONG_MAX`, so we’ll keep protecting against that.
Revert "Switch to the friendly `gsize` type"

This reverts commit 2b46558409d1bd4ba7b171b7086010ad358ab98f.
Merge pull request #24 from gjtorikian/a-few-secure-bolts

Tighten up some elements