diff --git a/geo/qgis/patches/patch-src_core_CMakeLists_txt b/geo/qgis/patches/patch-src_core_CMakeLists_txt
index 2ae4de4d9c2..0338815dc58 100644
--- a/geo/qgis/patches/patch-src_core_CMakeLists_txt
+++ b/geo/qgis/patches/patch-src_core_CMakeLists_txt
@@ -1,5 +1,11 @@
 https://github.com/qgis/QGIS/issues/61855
 
+chunk2 : try to fix the build with llvm22, cf https://github.com/qgis/QGIS/issues/66293
+
+set SKIP_PRECOMPILED_HEADERS ON on qgsexpression_texts.cpp otherwise clang complains about mismatching optimization levels:
+error: OptimizationLevel differs in precompiled file '/usr/obj/ports/qgis-4.0.3/build-amd64/src/core/CMakeFiles/qgis_core.dir/cmake_pch.hxx.pch' vs. current file
+
+use -O0 on textrenderer/qgsfontmanager.cpp otherwise c++ spins forever
 Index: src/core/CMakeLists.txt
 --- src/core/CMakeLists.txt.orig
 +++ src/core/CMakeLists.txt
@@ -12,7 +18,17 @@ Index: src/core/CMakeLists.txt
    SET(PDF4QT_BUILD_ONLY_CORE_LIBRARY TRUE)
    SET(PDF4QT_ENABLE_OPENGL FALSE)
    SUBDIRS(${CMAKE_SOURCE_DIR}/external/PDF4QT)
-@@ -2675,10 +2675,15 @@ target_include_directories(qgis_core PUBLIC
+@@ -2294,7 +2294,8 @@ if(MSVC)
+   )
+ else()
+   if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" AND (CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES RelWithDebInfo))
+-    set_source_files_properties(${CMAKE_CURRENT_BINARY_DIR}/qgsexpression_texts.cpp PROPERTIES COMPILE_FLAGS "-O1")
++    set_source_files_properties(${CMAKE_CURRENT_BINARY_DIR}/qgsexpression_texts.cpp PROPERTIES COMPILE_FLAGS "-O1" SKIP_PRECOMPILE_HEADERS ON)
++    set_source_files_properties(textrenderer/qgsfontmanager.cpp PROPERTIES COMPILE_FLAGS "-O0" SKIP_PRECOMPILE_HEADERS ON)
+     set_source_files_properties(proj/qgscoordinatereferencesystem.cpp PROPERTIES COMPILE_FLAGS "-mllvm -inline-threshold=128")
+   endif()
+ endif()
+@@ -2675,10 +2676,15 @@ target_include_directories(qgis_core PUBLIC
    ${CMAKE_SOURCE_DIR}/external/earcut
  )