math/bc-gh: Update to 3.1.1

Notable upstream changes:

## 3.1.0

The behavior that was adjusted was how code from the `-e` and `-f` arguments
(and equivalents) were executed. They used to be executed as one big chunk, but
in this release, they are now executed line-by-line.

The first bug fix in how output to `stdout` was handled in `SIGINT`. If a
`SIGINT` came in, the `stdout` buffer was not correctly flushed. In fact, a
clean-up function was not getting called. This release fixes that bug.

The second bug is in how `dc` handled input from `stdin`. This affected `bc` as
well since it was a mishandling of the `stdin` buffer.

The third fixed bug was that `bc` and `dc` could `abort()` (in debug mode) when
receiving a `SIGTERM`. This one was a race condition with pushing and popping
items onto and out of vectors.

The fourth bug fixed was that `bc` could leave extra items on the stack and
thus, not properly clean up some memory. (The memory would still get
`free()`'ed, but it would not be `free()`'ed when it could have been.)

The next two bugs were bugs in `bc`'s parser that caused crashes when executing
the resulting code.

The last two bugs were crashes in `dc` that resulted from mishandling of
strings.

## 3.0.2

This is a production release that adds `utf8` locale symlinks and removes an
unused `auto` variable from the `ceil()` function in the [extended math
library][16].

## 3.0.1

The second change is to make the new implementation of `ceil()` in `lib2.bc`
much more efficient.

(gdt)