KiCad doesn't compile with protobuf 6.x

Description

Fedora Rawhide is moving to protobuf 6.x, and KiCad doesn't build properly in that environment (build-error).

The log shows:

/usr/bin/ld.bfd: api/libkiapi.so.10.0.3: undefined reference to symbol '_ZN4absl12lts_2026010713hash_internal43CombineLargeContiguousImplOn64BitLengthGt32EmPKhm'
/usr/bin/ld.bfd: /usr/lib64/libabsl_hash.so.2601.0.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status

Steps to reproduce

Build error. Here is the full log:

build-1.log

KiCad Version

Here is the version info for a successful build using protobuf 3. The same code fails to build on rawhide when using protobuf 6.x.

Application: KiCad x86_64 on x86_64

Version: 10.0.3-1.fc44, release build

Libraries:
	wxWidgets 3.2.9 GLX
	FreeType 2.14.3
	HarfBuzz 14.1.0
	FontConfig 2.17.0
	libcurl/8.18.0 OpenSSL/3.5.5 zlib/1.3.1.zlib-ng brotli/1.2.0 libidn2/2.3.8 libpsl/0.21.5 libssh/0.12.0/openssl/zlib nghttp2/1.68.0 ngtcp2/1.22.1 nghttp3/1.15.0 mit-krb5/1.22.2 OpenLDAP/2.6.13

Platform: Fedora Linux 44 (Forty Four), 64 bit, Little endian, wxGTK, X11, x11, XFCE, xfce

Build Info:
	Date: May 14 2026 00:00:00
	wxWidgets: 3.2.9 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.90.0
	OCC: 7.9.1
	Curl: 8.18.0
	ngspice: 46
	Compiler: GCC 16.1.1 with C++ ABI 1021
	KICAD_IPC_API=ON
	KICAD_USE_PCH=OFF

Locale: 
	Lang: en_US
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)