From 31ed06327281d17e227ef1486da31f4ba9d50d90 Mon Sep 17 00:00:00 2001
From: Danilo Piparo <danilo.piparo@cern.ch>
Date: Tue, 15 Oct 2024 08:18:44 +0200
Subject: [PATCH] [cmake] Build clad with one core only

fixes #16654
---
 interpreter/cling/tools/plugins/clad/CMakeLists.txt | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/interpreter/cling/tools/plugins/clad/CMakeLists.txt b/interpreter/cling/tools/plugins/clad/CMakeLists.txt
index 6527060a7689b..2f4aa2dcd8b86 100644
--- a/interpreter/cling/tools/plugins/clad/CMakeLists.txt
+++ b/interpreter/cling/tools/plugins/clad/CMakeLists.txt
@@ -95,8 +95,12 @@ ExternalProject_Add(
              -DLLVM_DIR=${LLVM_BINARY_DIR}
              -DCLANG_INCLUDE_DIRS=${CLANG_INCLUDE_DIRS}
              ${_clad_extra_cmake_args}
-  BUILD_COMMAND ${CMAKE_COMMAND} --build . ${EXTRA_BUILD_ARGS}
-  INSTALL_COMMAND ${CMAKE_COMMAND} --build . ${EXTRA_BUILD_ARGS} --target install
+  # FIXME
+  # Building with 1 core is a temporary workaround for #16654 and has to be 
+  # there until the behaviour of the clad build on ubuntu 24.10 is understood.
+  # The performance penalty in the build is negligible.
+  BUILD_COMMAND ${CMAKE_COMMAND} --build . ${EXTRA_BUILD_ARGS} -j 1
+  INSTALL_COMMAND ${CMAKE_COMMAND} --build . ${EXTRA_BUILD_ARGS} -j 1 --target install
   BUILD_BYPRODUCTS ${CLAD_BYPRODUCTS}
   ${_clad_extra_settings}
   # We need the target clangBasic to be built before building clad. However, we