How to use the 'build_unflags' in platformio.ini

In order to remove some compiler message flooding, I wanted to turn off a specific compiler flag (-Wpointer-sign). My expectation was that I could use the ‘build_unflags’ in the platformio.ini, but the message warning: pointer targets in passing argument 1 of 'mbus_str_xml_encode' differ in signedness [-Wpointer-sign] keeps appearing. What am I missing here?


platform = espressif32
board = nodemcu-32s
upload_port = COM[4]
board_build.partitions = ESP32_OTA_4M.csv
; board_build.embed_files = src/cert/server_cert.pem
framework = espidf
monitor_speed = 115200
monitor_filters = esp32_exception_decoder
debug_tool = olimex-arm-usb-ocd-h
debug_speed = 6000
build_unflags = -Wpointer-sign
build_flags = -DCORE_DEBUG_LEVEL=5