STM32F0xx : GCC_ARM use a call to _start which performs

zero bss, C++ init and the call to main.
Remove direct call to __libc_init_array and main not needed
as _start is beeing called.

Author: jamike

targets/TARGET_STM/TARGET_STM32F0/TARGET_DISCO_F051R8/device/TOOLCHAIN_GCC_ARM/startup_stm32f051x8.S

@@ -99,11 +99,14 @@ LoopFillZerobss:
 
 /* Call the clock system intitialization function.*/
   bl  SystemInit
-/* Call static constructors */
-  bl __libc_init_array
-/* Call the application's entry point.*/
-  bl main
-  bl exit
+
+/**
+ * Calling the crt0 'cold-start' entry point. There __libc_init_array is called
+ * and when existing hardware_init_hook() and software_init_hook() before 
+ * starting main(). software_init_hook() is available and has to be called due 
+ * to initializsation when using rtos.
+*/
+  bl _start
 LoopForever:
     b LoopForever
 

targets/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F030R8/device/TOOLCHAIN_GCC_ARM/startup_stm32f030x8.S

@@ -99,8 +99,7 @@ LoopFillZerobss:
 
 /* Call the clock system intitialization function.*/
   bl  SystemInit
-/* Call static constructors */
-  bl __libc_init_array
+
 /* Call the application's entry point.*/
 //  bl main
   bl _start

targets/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F031K6/device/TOOLCHAIN_GCC_ARM/startup_stm32f031x6.s

@@ -99,8 +99,7 @@ LoopFillZerobss:
 
 /* Call the clock system intitialization function.*/
   bl  SystemInit
-/* Call static constructors */
-  bl __libc_init_array
+
 /* Call the application's entry point.*/
 //  bl main
   bl _start

targets/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F042K6/device/TOOLCHAIN_GCC_ARM/startup_stm32f042x6.s

@@ -131,8 +131,7 @@ LoopFillZerobss:
 
 /* Call the clock system intitialization function.*/
   bl  SystemInit
-/* Call static constructors */
-  bl __libc_init_array
+
 /* Call the application's entry point.*/
 //  bl main
   bl _start

targets/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F070RB/device/TOOLCHAIN_GCC_ARM/startup_stm32f070xb.S

@@ -99,8 +99,7 @@ LoopFillZerobss:
 
 /* Call the clock system intitialization function.*/
   bl  SystemInit
-/* Call static constructors */
-  bl __libc_init_array
+
 /* Call the application's entry point.*/
 //  bl main
   bl _start