Bug 936652 – media-gfx/openscad-2021.01-r5 fails to compile: config.h:147:2: error: error CGAL requires C++ 17

• Status: CONFIRMED
• Product: Gentoo Linux

[Description Agostino Sarubbo 2024-07-26 07:27:20 UTC]

https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: media-gfx/openscad-2021.01-r5 fails to compile.
Discovered on: amd64 (internal ref: ci)

Info about the issue:
https://wiki.gentoo.org/wiki/Project:Tinderbox/Common_Issues_Helper#CF0014

[Comment 1 Agostino Sarubbo 2024-07-26 07:27:22 UTC]

Created attachment 898344 [details]
build.log.xz

build log and emerge --info (compressed because it exceeds attachment limit, use 'xzless' to read it)

[Comment 2 Michael Weiser 2024-08-06 12:17:15 UTC]

As the message says, this is due to sci-mathematics/cgal-6.0_beta1 requiring C++ 17: https://www.cgal.org/2024/06/21/cgal60-beta1/#general-changes.

Downgrading to 5.6.1 solves the issue. So does patching openscad's c++std.pri like so:

--- openscad-2021.01/c++std.pri.prog	2024-08-05 21:35:46.484782450 +0200
+++ openscad-2021.01/c++std.pri	2024-08-05 21:35:55.098192923 +0200
@@ -26,8 +26,8 @@
 }
 
 c++std {
-  CONFIG += c++14 strict_c++
-  message("Using C++14")
+  CONFIG += c++17 strict_c++
+  message("Using C++17")
 
   *clang*: {
       # 3rd party libraries will probably violate this for a long time

[Comment 3 Michael Weiser 2024-08-06 14:18:33 UTC]

See also https://bugs.gentoo.org/937456.

[Comment 4 Rémi Cardona 2024-10-03 07:06:00 UTC]

patch in comment #2 works for me as well. Freecad then built correctly (can't tell how or where openscad is used by it and thus if it's all ok).