symlink mib hrl output in apps `include' directories

[talentdeficit]

this restores compatibility with rebar2 and erlang.mk

the fix is somewhat of a hackjob but without refactoring rebar_base_compiler pretty substantially there's no good way to pass the mib compiler the extra information it needs

[ferd]

+1

[goertzenator]

This PR puts the MIB include file into 2 locations, the application include and priv/mibs/include. Is there good reason to place it into priv/mibs/include? Perhaps @toland from PR #948 could comment on the prevalence priv/mibs/include. If there really are projects in the wild that use priv/mibs/include, then +1 to this.

When I learned rebar3, unraveling what was going on in the _build dir was frustrating. I write this comment thinking of the future me's who will see the 2 include instances and wonder what's going on.

[talentdeficit]

i am ok with just putting the header file in include but i know nothing about mibs or how they are used so i'm inclined to just do whatever is suggested

ideally someone would write a decent mibs provider plugin and we could drop mibs support from rebar3

[toland]

FWIW, I was just trying to preserve what I thought was the original author's intent. I have always put the hrl files in include, but I thought maybe the the original author knew something I don't :)

My vote would be to drop the hrl files in the project include directory and be done with it.

[talentdeficit]

i've altered this pr to remove the header file in priv/mibs/include and to just move it directly to the applications include directory

[ferd]

Still +1.

[goertzenator]

Looks good! +1.

[toland]

+1