Improve deps handling in CMake, make possible to not use libs from deps folders, and to use deps folders on unsupported platforms when provided

[illwieckz]

Improve deps handling in CMake

cmake: use extra external deps if the directory exist and add an option to not use libs from them

• Add an option to not build and link against libraries from external_deps
  • Purposed to make possible to build on linux using system-provided SDL3 instead of the one in DEPS, in the rare case the system already provides SDL3.
  • Purposed to make possible to build on macos-arm64 using the macos-amd64 deps archive to find the NaCl runtime, relying on the system (example: brew) to find libraries.
  • Purposed to make possible to build on freebsd using the linux deps archive to find the NaCl runtime, relying on the system to find libraries.
• Use the macos-amd64 deps on macos-arm64 only if the user didn't provide a macos-arm64 deps folder by himself.
• Use the linux deps on freebsd only if the user didn't provide a freebsd deps folder by himself.
• Use the deps folder if the user provided it by himself, even if we don't know yet about this system or architecture or we don't support that.

---

cmake: only set -march if the architecture is known

Do not set an empty -march= option when attempting to build on an unknown system.

We only print a warning when attempting to build on an unknown system, so this should not expect it is never built for an unknown system.

[illwieckz]

The first commit is important as I guess some distros like Arch would want to update their AUR script to use the Arch-provided SDL3 instead of the on in the deps archive, that one we provide because SDL3 is to new and many stable releases didn't packaged it yet.

It should also make easier for building on extra plaforms (not supported in unizip, but buildable, like macos-arm64 and freebsd).

[slipher]

I don't get how the riscv support is supposed to serve as a demonstration for any of the other stuff in the PR. Given that you added it to the external_deps build script, then shouldn't it just work with the existing infrastructure once you have run build.sh? Or if you didn't run build.sh, you are already allowed to proceed without a deps dir, which is fine if the platform doesn't support NaCl anyway. By the way, does it actually run or you only tested building?

The first commit is important as I guess some distros like Arch would want to update their AUR script to use the Arch-provided SDL3 instead of the on in the deps archive, that one we provide because SDL3 is to new and many stable releases didn't packaged it yet.

Hmm, if I were the build script maintainer I would definitely prefer to only copy the desired components into the deps dir, instead of putting them in there but then relying on an option to hopefully not use the libs that were provided.

For ARM Macs why don't we do it properly and add its platform to build.sh with a single naclsdk target that does the same thing as on Intel Macs? Looking in multiple dirs is unnecessarily confusing.

[slipher]

How about adding an option NACL_DEPS_DIR? If set this would be the base path for NaCl-related stuff. This could be helpful in the Arch PKGBUILD, arm64 Mac, and FreeBSD cases. That would be simpler than referring to the entire deps dir of some platform but then selectively disabling parts of it.

[illwieckz]

I removed the riscv64 demonstration. That acted as a demonstration for:

1. using a deps dir if it's provided beforehand, even if not being a known platform.
2. using an architecture for which we don't set a -march option.

I now have a much larger branch on my end with that riscv stuff, but also macos-arm64 build (probably ready to use) and WIP freebsd. This was enough for me to test that CMake code.

My freebsd experiment was enough to verify that yes it was using the linux archive without the SDL3 libs if no freebsd deps is provided, but as soon as I provide a freebsd deps folder myself, it uses the provided deps folder.

I assume that part would work as well for macos-arm64.

Also it looks like that freebsd experiment validated that the option to not use libs from a deps dir, even when using that deps dir, is working, which would be useful for linux too (when wanting to enforce linking everything against the system).

Now what's remaining in that branch is the CMake stuff for that deps detection and deps lib skip, plus the -march stuff that is very small.

[illwieckz]

Hmm, if I were the build script maintainer I would definitely prefer to only copy the desired components into the deps dir, instead of putting them in there but then relying on an option to hopefully not use the libs that were provided.

The packager can either run external_deps/build.sh naclsdk naclruntime beforehand to only get that, or can rely on the prepackaged deps archive and use the variable to ignore the libs. There is no reason CMake would look for libs in the deps archive if we don't explicitly tell CMake to look there for libs.

[illwieckz]

Flatpak doesn't allow download as part of the build process, so if Flatpak provides SDL3, we better use the option to skip the libs, as we download the deps archive before the build already.

[illwieckz]

I added some logging so it's now reporting what deps folder it is using, and it reports if it uses libs from the deps folder or not.

[illwieckz]

With -DUSE_EXTERNAL_DEPS_LIBS=ON:

-- Found Threads: TRUE  
-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libOpenGL.so   
-- Found OpenGL ABI: LEGACY
-- Found OpenGL library: /usr/lib/x86_64-linux-gnu/libGL.so
-- Found ZLIB: deps/linux-amd64-default_11/lib/libz.a (found version "1.3.1")  
-- Found Nettle: deps/linux-amd64-default_11/lib/libnettle.a  
-- Found GMP: deps/linux-amd64-default_11/lib/libgmp.a
-- Found CURL: deps/linux-amd64-default_11/lib/cmake/CURL/CURLConfig.cmake (found version "8.15.0")  
-- Found Ogg: deps/linux-amd64-default_11/lib/libogg.a  
-- Found Vorbis: deps/linux-amd64-default_11/lib/libvorbis.a  
-- Found Opus: deps/linux-amd64-default_11/lib/libopusfile.a  
-- Found WebP: deps/linux-amd64-default_11/lib/libwebp.a  
-- Performing Test _WEBP_COMPILATION_TEST
-- Performing Test _WEBP_COMPILATION_TEST - Success
-- Found JPEG: deps/linux-amd64-default_11/lib/libjpeg.a (found version "80") 
-- Found PNG: deps/linux-amd64-default_11/lib/libpng.a (found version "1.6.50") 
-- Found Freetype: /usr/lib/x86_64-linux-gnu/libfreetype.so (found version "2.13.2") 
-- Found GLEW: deps/linux-amd64-default_11/lib/libGLEW.a  
-- Found OpenAL: deps/linux-amd64-default_11/lib/libopenal.a  
-- Generating DaemonBuildInfo/Engine.cpp
-- Generating DaemonBuildInfo/Engine.h

With -DUSE_EXTERNAL_DEPS_LIBS=OFF:

-- Found Threads: TRUE  
-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libOpenGL.so   
-- Found OpenGL ABI: LEGACY
-- Found OpenGL library: /usr/lib/x86_64-linux-gnu/libGL.so
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.3")  
-- Found Nettle: /usr/lib/x86_64-linux-gnu/libnettle.so  
-- Found GMP: /usr/lib/x86_64-linux-gnu/libgmp.so
-- Found CURL: /usr/lib/x86_64-linux-gnu/libcurl.so (found version "8.5.0")  
CMake Error at CMakeLists.txt:792 (find_package):
  Could not find a package configuration file provided by "SDL3" with any of
  the following names:

    SDL3Config.cmake
    sdl3-config.cmake

  Add the installation prefix of "SDL3" to CMAKE_PREFIX_PATH or set
  "SDL3_DIR" to a directory containing one of the above files.  If "SDL3"
  provides a separate development package or SDK, be sure it has been
  installed.


-- Configuring incomplete, errors occurred!

So the USE_EXTERNAL_DEPS_LIBS option is working as expected.

[illwieckz]

I merge this for the release.