This replaces all of the Apache blurbs at the start of each file with an
`# SPDX-License-Identifier: Apache-2.0` string. It also fixes existing
uses to be consistent in capitalization, and to be placed above any
copyright notices.
This removes nearly 3000 lines of boilerplate from the project (only
python files), which no developer cares to look at.
SPDX is in common use, particularly in the Linux kernel, and is the
recommended format for Meson's own `project(license: )` field
According to the Meson documentation, optimization level 3 should
set the highest possible optimization for the compiler in use.
In Metrowerks, this is 'O4,p'. However, Meson's Metrowerks
implementation mapped opt level 3 to '-O3'. This has been fixed.
The args were in both buildtype and optimization. This broke buildtypes other
than plain or custom unless manually setting the optimization level to
0, because Metrowerks chokes on duplicate arguments.