Our gcc does not support -fno-fat-lto-objects:

$ /usr/gcc/13/bin/gcc -flto=auto -fno-fat-lto-objects SOURCE.c
cc1: error: '-fno-fat-lto-objects' are supported only with linker plugin
$

See also: https://gitlab.kitware.com/cmake/cmake/-/issues/23136

--- cmake-3.30.1/Modules/Compiler/GNU.cmake.orig
+++ cmake-3.30.1/Modules/Compiler/GNU.cmake
@@ -151,13 +151,6 @@
       list(APPEND __lto_flags -flto)
     endif()
 
-    if(NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4.7 AND NOT APPLE)
-      # '-ffat-lto-objects' introduced since GCC 4.7:
-      # * https://gcc.gnu.org/onlinedocs/gcc-4.6.4/gcc/Option-Summary.html (no)
-      # * https://gcc.gnu.org/onlinedocs/gcc-4.7.4/gcc/Option-Summary.html (yes)
-      list(APPEND __lto_flags -fno-fat-lto-objects)
-    endif()
-
     set(CMAKE_${lang}_COMPILE_OPTIONS_IPO ${__lto_flags})
 
     # Need to use version of 'ar'/'ranlib' with plugin support.