Linking against `libmbed-os.a` misses necessary override of weak symbol `HAL_InitTick`

[bikeNomad]

I'm compiling a couple of programs for the STM32F072 against a pre-built libmbed-os.a

First, I build libmbed-os.a using:

MBED_OS_DIR=mbed-os mbed compile -t GCC_ARM -m STM32F072VB \
	--build mbed-os-build \
	--library --source mbed-os --custom-targets Targets \
	--profile debug --profile Common/mydebug.json

rm $(find mbed-os-build -name '*.o')

Then I compile my program sources and link against libmbed-os.a using this command line:

MBED_OS_DIR=mbed-os mbed compile -t GCC_ARM -m STM32F072VB --build ui-build \
	--source UserInterface --source ../CAN_API --source Targets \
	--custom-targets Targets \
	--source Common --source mbed-os-build \
	--profile debug --profile Common/mydebug.json -v

However, the linker is using the weak HAL_InitTick from
mbed-os/targets/TARGET_STM/TARGET_STM32F0/device/stm32f0xx_hal.c
instead of the necessary override from mbed-os/targets/TARGET_STM/hal_tick_overrides.c

$ arm-none-eabi-nm -A -C mbed-os-build/libmbed-os.a  | grep HAL_InitTick

mbed-os-build/libmbed-os.a:stm32f0xx_hal.o:00000000 W HAL_InitTick
mbed-os-build/libmbed-os.a:stm32f0xx_hal_rcc.o:         U HAL_InitTick
mbed-os-build/libmbed-os.a:hal_tick_overrides.o:00000000 T HAL_InitTick

$ arm-none-eabi-nm -A -C ui-build/UserInterface.elf | grep HAL_InitTick

ui-build/UserInterface.elf:0800583e W HAL_InitTick

In the ui-build/UserInterface.map file I see:

 .text.HAL_InitTick
  0x000000000800583e       0x24 mbed-os-build/libmbed-os.a(stm32f0xx_hal.o)

Copying mbed-os/targets/TARGET_STM/hal_tick_overrides.c into my custom_targets directory
and re-building fixes the problem.

But I don't want to have to do this.

UserInterface/mbed_app.json looks like this:

{
  "macros": [ "USER_INTERFACE_MCU=1", "NDEBUG=1", "MAX_VARIABLES=30" ],
  "target_overrides": {
    "*": {
      "drivers.spi_count_max": 0,
      "events.shared-highprio-stacksize": 0,
      "events.shared-stacksize": 1024,
      "events.shared-dispatch-from-application": true,
      "platform.crash-capture-enabled": true,
      "platform.error-filename-capture-enabled": false,
      "platform.memory-tracing-enabled": false,
      "platform.minimal-printf-enable-64-bit": false,
      "platform.stack-stats-enabled": false,
      "platform.stdio-buffered-serial": false,
      "platform.stdio-flush-at-exit": false,
      "platform.use-mpu": false,
      "rtos.idle-thread-stack-size": 512,
      "rtos.main-thread-stack-size": 1024,
      "rtos.thread-stack-size": 1024,
      "rtos.timer-thread-stack-size": 768,
      "target.boot-stack-size": "0x400",
      "target.console-uart": false,
      "target.console-uart-flow-control": false 
    }
  }
}

Common/mydebug.json looks like this:

{
    "GCC_ARM": {
        "common": [
            "-ICommon/include",
            "-ITargets/targets/TARGET_STM/TARGET_STM32F0/TARGET_STM32F072VB",
            "-I../CAN_API",
            "-I../CAN_API/MessageHandling/include",
            "-I../CAN_API/MessageHandling/include/mbed" ],
        "c": ["-std=gnu11"],
        "cxx": ["-std=gnu++14", "-fno-rtti", "-fno-exceptions" ]
    }
}

My Targets/custom_targets.json looks like this:

{
  "STM32F072VB": {
    "inherits": ["NUCLEO_F072RB"],
    "extra_labels_add": ["STM32F072VB"],
    "device_name": "STM32F072VB",
    "default_lib": "small",
    "supported_form_factors": [],
    "features": [],
    "components": [],
    "overrides": {
        "clock_source": "USE_PLL_HSE_XTAL"
    }
  }
}

[ciarmcom]

Internal Jira reference: https://jira.arm.com/browse/IOTBTOOL-516