make a platform_quirks.h

[craigcitro]

There are lots of platform-specific quirks in various parts of the Sage library. For instance, see the #if defined(__sun) at the top of partitions_c.cc (and partitions_c.h). These should be moved to a single header in libcsage.

Component: build

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/4484

[craigcitro]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-There are lots of platform-specific quirks in various parts of the Sage library. For instance, see the `#if defined(__sun)` at the top of `partitions_c.cc` (`partitions_c.h`). These should be moved to a single header in `libcsage`.
+There are lots of platform-specific quirks in various parts of the Sage library. For instance, see the `#if defined(__sun)` at the top of `partitions_c.cc` (and `partitions_c.h`). These should be moved to a single header in `libcsage`.

[jdemeyer]

comment:3

We managed to live without this, so I guess it's not really needed.

[jdemeyer]

Reviewer: Jeroen Demeyer