[4.5] builtin_libjpeg_turbo=False not working

[tgurr]

Tested versions

Godot Engine v4.5.stable.exherbo.876b29033

System information

Godot v4.5.stable (876b29033) - Exherbo #1 SMP PREEMPT_DYNAMIC Mon Sep 15 14:43:55 CEST 2025 on X11 - X11 display driver, Multi-window, 2 monitors - Vulkan (Forward+) - integrated Intel(R) UHD Graphics 770 (ADL-S GT1) - 12th Gen Intel(R) Core(TM) i5-12500 (12 threads) - 15.27 GiB memory

Issue description

builtin_libjpeg_turbo=False produces a binary not linked against system libjpeg-turbo:

ldd /usr/x86_64-pc-linux-gnu/bin/godot | grep jpeg returns nothing, while it works for other libraries like e.g. libpng:

ldd /usr/x86_64-pc-linux-gnu/bin/godot | grep png
        libpng16.so.16 => /usr/x86_64-pc-linux-gnu/lib/libpng16.so.16 (0x00007fbfc31aa000)

To be sure the bundled libraries are not used during build we also remove them, e.g. for libpng:

rm -rf thirdparty/libpng

So when adding libjpeg-turbo to that list rm -rf thirdparty/libjpeg-turbo the build fails with:

[...]
scons: *** [bin/obj/thirdparty/libjpeg-turbo/src/jcapistd_8.linuxbsd.editor.x86_64.o] Source `thirdparty/libjpeg-turbo/src/jcapistd.c' not found, needed by target `bin/obj/thirdparty/libjpeg-turbo/src/jcapistd_8.linuxbsd.editor.x86_64.o'.

also indicating that the bundled copy is still used.

Complete build log: godot-4.5_build.log

Steps to reproduce

1. have libjpeg-turbo installed system-wide
2. remove from godot 4.5 sources rm -rf thirdparty/libjpeg-turbo
3. try to build with builtin_libjpeg_turbo=False

Minimal reproduction project (MRP)

[akien-mga]

I noticed it too when updating my Fedora package and wrote a fix already: #110540.

[tgurr]

I noticed it too when updating my Fedora package and wrote a fix already: #110540.

Thanks, confirmed working for me having built godot 4.5 with the patch applied:

$ ldd /usr/x86_64-pc-linux-gnu/bin/godot | grep jpeg
        libturbojpeg.so.0 => /usr/x86_64-pc-linux-gnu/lib/libturbojpeg.so.0 (0x00007fcaeaf99000)