* moves dolphin-specific settings out of Base.props
* creates exports.props for externals, allowing to easily import
individual Externals
* corrects some cruft that accumulated and probably contributed
to msbuild overbuilding
Ninja puts way more effort into compiling targets in parallel, and
ignores dependenceis until link time.
So we need to jump though hoops to force ninja to compile
pch.cpp before any targets which depend on the PCH.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
Add external include paths to ExternalIncludePath instead of
AdditionalIncludeDirectories. msbuild appends these paths to
EXTERNAL_INCLUDE env var, which is passed to /external:env:.
Specify /external:W0 and /external:templates-, with override for
DolphinQt for the template flag, since Qt 5.15.0 causes some warnings
in qmap.h
fmt/format.h is included in the PCH, so we need to make sure fmt is
actually in the include path.
Not sure how Visual Studio + CMake manages to build without this.
Intellisense doesn't like defines in PCH files, and it doesn't like the deleted
constructor for BitField. (I think it's being overly strict about the
"must have no non-default constructors" rule for classes in unions.)
