SCons: Add CPPEXTPATH for external includes (reverted)

[Repiteo]

• Supersedes SCons: Treat thirdparty includes as external #101196

A reimagining of the above PR. Instead of adding a dedicated method for external includes, this instead opts to add an entirely new SCons variable to append pathing to. This keeps the existing logic almost completely unchanged, with only generic renames being needed most of the time. Much like the previous PR, this removes the need for the warning wrappers around external includes, so those have been removed as necessary.

[Repiteo]

Hmm, so the different platforms handle thirdparty includes differently. That's... Annoying

[akien-mga]

That looks pretty promising! I like the idea. I had missed the previous attempt.

Hmm, so the different platforms handle thirdparty includes differently.

What do you mean exactly?

[akien-mga]

The CI build with SCons 4.0.0 has a type error:
https://github.com/godotengine/godot/actions/runs/14204122051/job/39797772814?pr=104893

[Repiteo]

The CI build with SCons 4.0.0 has a type error:

Oh! That must've been what was throwing me off earlier. Hopefully it's not a platform-specific issue after all

[akien-mga]

This might cause warnings to be raised by the GDExtension build option for text servers, CC @bruvzg.

We might want to add the same system to godot-cpp.

[Repiteo]

I'll make a followup PR there once this is merged

[bruvzg]

It likely will, but godot-cpp does not use Werror in any config, so it won't break it. But it definitely worth adding the support for the same system to godot-cpp regardless.

[akien-mga]

Looks great!

[corngood]

This is causing problems on nixpkgs, where we build for linux with sowrap disabled and with builtin freetype.

scons alsa=true ccflags=-fno-strict-aliasing dbus=true debug_symbols=true fontconfig=true linkflags=-Wl,--build-id module_mono_enabled=false platform=linuxbsd precision=single production=true pulseaudio=true speechd=true target=editor touch=true udev=true use_sowrap=false wayland=true x11=true lto=none verbose=true

One of the pkgconfig dependencies (fontconfig) adds a -I for freetype. Previously, env_freetype.Prepend(CPPPATH=[thirdparty_dir + "/include"]) would ensure the local path was checked first.

This results in a link error:

godot-mono> /nix/store/c43ry7z24x3jhnjlj4gpay8a4g2p3x1h-binutils-2.44/bin/ld: /nix/store/95gvjj2dq0fn7x95zppnkpbril4djmnn-freetype-2.13.3/lib/libfreetype.so: undefined reference to symbol 'BZ2_bzDecompress'
godot-mono> /nix/store/c43ry7z24x3jhnjlj4gpay8a4g2p3x1h-binutils-2.44/bin/ld: /nix/store/x1nn5jrx1im7wmmn1xmpjvyf072s5k75-bzip2-1.0.8/lib/libbz2.so.1: error adding symbols: DSO missing from command line
godot-mono> collect2: error: ld returned 1 exit status
godot-mono> scons: *** [bin/godot.linuxbsd.editor.x86_64.mono] Error 1
godot-mono> scons: building terminated because of errors.

There are various ways this could be fixed, but I'm not sure what approach to take. #109749 seems similar, and resulted in reverting the CPPEXTPATH change.

[Repiteo]

Shoot, it seems like this setup really struggles to account for dependencies defining includes in different styles. It might warrant revisiting this system altogether, which is annoying but I don't want this to be a recurring issue

[corngood]

Shoot, it seems like this setup really struggles to account for dependencies defining includes in different styles. It might warrant revisiting this system altogether, which is annoying but I don't want this to be a recurring issue

I'm not sure the old way was any more 'right' in general. In my build environment, I have:

$ pkg-config --cflags fontconfig
-I/nix/store/vkb9z2p7mzn0b2282vfxfg6i79rwzicl-fontconfig-2.16.2-dev/include -I/nix/store/l0giy21i8c3acqsp2y678h5x4m95v7l0-freetype-2.13.3-dev/include/freetype2
$ pkg-config --libs fontconfig
-L/nix/store/kld68jc4zmliifsvhq8gwrn85zxr8vr4-fontconfig-2.16.2-lib/lib -L/nix/store/95gvjj2dq0fn7x95zppnkpbril4djmnn-freetype-2.13.3/lib -lfontconfig -lfreetype

What if the vendored freetype causes problems with fontconfig?

I think what I'd like to do in nixpkgs is just turn off as much of the builtin_ stuff as possible.

[akien-mga]

We should revert this given the number of regressions it's causing, for limiting benefits.

See:

• Can no longer build godot and godot-nir-static from source together #106376
• SCons: Add CPPEXTPATH for external includes (reverted) #104893 (comment)
• Jolt: Update to 5.4.0 #110965
• Vulkan: Add macros to avoid compilation issues with missing symbols in Vulkan 1.0 #111094