Remove -nostartfiles linker option from bootloader (#5996)

* Remove -nostartfiles linker option from bootloader

Compiling with this option creates undefined references to _fini

* Remove now empty init.c

radio/src/targets/common/arm/stm32/bootloader/CMakeLists.txt

@@ -73,7 +73,6 @@ set(BOOTLOADER_SRC
   ../usb_bsp.c
   ../usb_driver.cpp
   ../flash_driver.cpp
-  init.c
   boot.cpp
   bin_files.cpp
   )
@@ -112,7 +111,7 @@ remove_definitions(-DCLI)
 remove_definitions(-DUSB_SERIAL)
 add_definitions(-DBOOT)
 
-set(CMAKE_EXE_LINKER_FLAGS "-mcpu=${MCU} -mthumb -nostartfiles -lm -T${RADIO_SRC_DIRECTORY}/targets/${TARGET_DIR}/stm32_ramboot.ld -Wl,-Map=bootloader.map,--cref,--no-warn-mismatch,--gc-sections")
+set(CMAKE_EXE_LINKER_FLAGS "-mcpu=${MCU} -mthumb -lm -T${RADIO_SRC_DIRECTORY}/targets/${TARGET_DIR}/stm32_ramboot.ld -Wl,-Map=bootloader.map,--cref,--no-warn-mismatch,--gc-sections")
 
 add_executable(bootloader ${BOOTLOADER_SRC})
 add_dependencies(bootloader ${BITMAPS_TARGET} firmware_translations)

radio/src/targets/common/arm/stm32/bootloader/boot.cpp

@@ -526,8 +526,4 @@ int main()
   }
 
   return 0;
-}
-
-#if defined(PCBHORUS)
-void *__dso_handle = 0;
-#endif
+}

radio/src/targets/common/arm/stm32/bootloader/init.c

@@ -1,4 +0,0 @@
-void _init (void)
-{
-  
-}