[C++] Compatibility macros for exported extern template class declarations

[asfimport]

See all the compiler warnings in our Windows builds

https://ci.appveyor.com/project/ApacheSoftwareFoundation/arrow/build/1.0.652

Also, consider the hacks we have around gcc/clang disagreement about visibility about the use of extern template:

https://github.com/apache/arrow/blob/master/cpp/src/arrow/array.h#L508

I suspect we may want some macros to help with compiler differences about such issues, possibly to go in https://github.com/apache/arrow/blob/master/cpp/src/arrow/util/visibility.h

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

_{Note: This issue was originally created as ARROW-627. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
PR: #447

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 447
#447