Older gcc versions (4.x) require passing --std=c99 compiler flag to
prevent warnings from being emitted. Instead of setting it for each
dependency, it's easier to just pass the CMAKE_C_STANDARD flag to all
dependencies. This also prevents the scenario of us forgetting to set it
if we add new dependencies.
It's simpler to let cmake figure out what flags to add to each platforms
to create position independent code rather than handling it ourselves.
Also remove code that sets POSITION_INDEPENDENT_CODE property on SHARED
and MODULE libraries, as it's already on by default.
Problem:
Dirs "config", "packaging", and "third-party" are all closely related
but this is not obvious from the layout. This adds friction for new
contributors.
Solution:
- rename config/ to cmake.config/
- rename test/config/ to test/cmakeconfig/ because it is used in Lua
tests: require('test.cmakeconfig.paths').
- rename packaging/ to cmake.packaging/
- rename third-party/ to cmake.deps/ (parallel with .deps/)
