Disable mimalloc by default / enable explicitly if needed (#19118)

CMakeLists.txt

@@ -208,8 +208,27 @@ mark_as_advanced(BUILD_FOR_PACKAGING)
 cmake_dependent_option(FORCE_LEGACY_LIBBPF "Force usage of libbpf 0.0.9 instead of the latest version." False "ENABLE_PLUGIN_EBPF" False)
 mark_as_advanced(FORCE_LEGACY_LIBBPF)
 
-cmake_dependent_option(ENABLE_MIMALLOC "Enable mimalloc allocator" ON
-        "CMAKE_MINOR_VERSION GREATER_EQUAL 18; CMAKE_SIZEOF_VOID_P EQUAL 8; NOT OS_FREEBSD; NOT OS_MACOS; NOT OS_WINDOWS; NOT ENABLE_ADDRESS_SANITIZER" OFF)
+option(ENABLE_MIMALLOC "Enable mimalloc allocator" OFF)
+
+if(ENABLE_MIMALLOC)
+    if(CMAKE_MINOR_VERSION LESS 18)
+        message(WARNING "Mimalloc disabled: Requires CMake version 3.18 or higher.")
+        set(ENABLE_MIMALLOC OFF CACHE BOOL "Enable mimalloc allocator" FORCE)
+    elseif(CMAKE_SIZEOF_VOID_P LESS 8)
+        message(WARNING "Mimalloc disabled: Only supported on 64-bit platforms.")
+        set(ENABLE_MIMALLOC OFF CACHE BOOL "Enable mimalloc allocator" FORCE)
+    elseif(OS_FREEBSD OR OS_MACOS OR OS_WINDOWS)
+        message(WARNING "Mimalloc disabled: Not supported on FreeBSD, macOS, or Windows.")
+        set(ENABLE_MIMALLOC OFF CACHE BOOL "Enable mimalloc allocator" FORCE)
+    elseif(ENABLE_ADDRESS_SANITIZER)
+        message(WARNING "Mimalloc disabled: Cannot be used with Address Sanitizer.")
+        set(ENABLE_MIMALLOC OFF CACHE BOOL "Enable mimalloc allocator" FORCE)
+    else()
+        message(STATUS "Mimalloc is enabled.")
+    endif()
+else()
+    message(STATUS "Mimalloc is disabled.")
+endif()
 
 if(ENABLE_MIMALLOC)
         function(netdata_add_mimalloc)