Summary:
This adds support for having lookup from pointer to decl in C frontend
NOTE: with this diff atdgen 1.6 or later is required.
To upgrade atdgen, please run `opam install atdgen.1.6.0`
Summary: @publicThe first argument of builtin calls in C gets translated twice, which is bad if the argument is a side-effecting expression like a function call.
Test Plan: Attached test previously reported a memory leak because the translation introduces an extra call to malloc(), now reports nothing.