notmuch/compat

This directory consists of three things:

1. Small programs used by the notmuch configure script to test for the
   availability of certain system features, (library functions, etc.).

   For example: have_getline.c

2. Compatibility implementations of those system features for systems
   that don't provide their own versions.

   For example: getline.c

   The compilation of these files is made conditional on the output of
   the test programs from [1].

3. Macro definitions abstracting compiler differences (e.g. function
   attributes).

   For example: function-attributes.h
