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.
Any file which includes scmrev.h must be rebuilt when scmrev.h
is regenerated. By not including scmrev.h from any file other
than Version.cpp, incremental builds become a little faster.
Ideally Common.h wouldn't be a header in the Common library, and instead be renamed to something else, like PlatformCompatibility.h or something, but even then, there's still some things in the header that don't really fall under that label
This moves the version strings out to their own version header that doesn't dump a bunch of other unrelated things into scope, like what Common.h was doing.
This also places them into the Common namespace, as opposed to letting them sit in the global namespace.
OS X uses a case insensitive filesystem by default: when I try to build,
a system header does #include <assert.h>, which picks up
Source/Core/Common/Assert.h. This only happens because CMakeLists adds
'${PROJECT_BINARY_DIR}/Source/Core/Common' as an include directory: in
an out-of-tree build, that directory contains no other source files, but
in an in-tree build PROJECT_BINARY_DIR is just the source root.
This is only used for scmrev.h. Change the include directory to
'${PROJECT_BINARY_DIR}/Source/Core' and the include to
"Common/scmrev.h", which is more consistent with normal headers anyway.
This is good hygiene, and also happens to be required to build Dolphin
using Clang modules.
(Under this setup, each header file becomes a module, and each #include
is automatically translated to a module import. Recursive includes
still leak through (by default), but modules are compiled independently,
and can't depend on defines or types having previously been set up. The
main reason to retrofit it onto Dolphin is compilation performance - no
more textual includes whatsoever, rather than putting a few blessed
common headers into a PCH. Unfortunately, I found multiple Clang bugs
while trying to build Dolphin this way, so it's not ready yet, but I can
start with this prerequisite.)
Our defines were never clear between what meant 64bit or x86_64
This makes a clear cut between bitness and architecture.
This commit also has the side effect of bringing up aarch64 compiling support.
Pierre Bourdon