meson: Fix compatibility with autotools
This MR improves the consistency and feature parity between meson build system and autotools. Improvements in meson are a follows:
- INPUTTHREAD is now consistent with autotools. Also fixes missing pthread detection.
- The configuration macros are consistently defined with value (e.g.
#define FOO 1
instead of#define FOO
). - Unit tests are now compiled without LTO which is broken in certain configurations.
Fixes #936 (closed). Fixes #1116 (closed).
Edited by Povilas Kanapickas