* ci: check runtime symbol policy on travis and Appveyor
* tune check-symbol-names:
** ignore all local symbol
** ignore Caml_ prefix
** ignore x86: pic-related symbols
** windows: ignore debugging, unicode and wmain symbols
Currently our CI machine on FreeBSD fails to build with the following
error message:
```
bytecomp/generate_runtimedef.sh runtime/caml/fail.h runtime/primitives > bytecomp/runtimedef.ml
/bin/sh: bytecomp/generate_runtimedef.sh: not found
```
This PR converts all the files with a `/bin/bash` shebang to
`/usr/bin/env bash`. Some files use `/bin/sh` instead, and they are
unchanged. It may be the case that some 'bash' files could in fact run
using 'sh', but checking this requires more work and I decided to
follow the original author's intent.
(Personally I like using bash explicitly as it gives a consistent
programming environment that I can easily test on my machine; but this
should not be at the expense of portability.)
Florian Angeletti
Gabriel Scherer
David Allsopp
Stephen Dolan