build: disable precompiled headers when using GCC >=12.2

Prevents out-of-bounds error bug present in GCC >=12.2 that happens when precompiled headers are used with c++20

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106799

CHANGES.md

@@ -28,6 +28,9 @@ Changes from ns-3.40 to ns-3-dev
 
 ### Changes to build system
 
+* In preparation to enable C++20, the following actions have been taken due to compiler issues:
+  * Precompiled headers have been disabled in GCC versions >= 12.2.
+
 ### Changed behavior
 
 Changes from ns-3.39 to ns-3.40

build-support/macros-and-definitions.cmake

@@ -244,6 +244,13 @@ if("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
     # ns3-module-macros.cmake.
     set(GCC8 TRUE)
   endif()
+  if((CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "12.2.0"))
+    # PCH causes weird errors on certain versions of GCC when C++20 is enabled
+    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106799
+    set(NS3_PRECOMPILE_HEADERS OFF
+        CACHE BOOL "Precompile module headers to speed up compilation" FORCE
+    )
+  endif()
   set(GCC TRUE)
   add_definitions(-fno-semantic-interposition)
   if(${NS3_COLORED_OUTPUT} OR "$ENV{CLICOLOR}")