[OOB 5.6] ARMC6 build does not startup on NRF52_DK target

[toyowata]

Description

• Type: Bug
• Priority: Major

---

Bug

On NRF52_DK target, mbed-os-exampl-blinky does not work by ARMC6 toolchain build.

Target
NRF52_DK

Toolchain:
ARMC6

Toolchain version:
Product: MDK Professional 5.24
Component: ARM Compiler 6.7
Tool: armclang [5c9efc00]

mbed-cli version:
1.2.0

mbed-os sha:
mbed-os (a4056fb)

DAPLink version:
nrf51822aa_atsam3u2c_if_mbed_V0219_02022016.bin

Expected behavior
mbed-os-exampl-blinky should blink.

Actual behavior
mbed-os-exampl-blinky does not blink.

Steps to reproduce

$ mbed import mbed-os-example-blinky
$ cd mbed-os-example-blinky
$ mbed update mbed-os-5.6-oob
$ mbed compile -m NRF52_DK -t ARMC6 -f

Additional Information

ARM build (version 5.06) does not have any problem.
ARMC6 build does not seem to startup correctly. See greentea test result below for more detail.

• ARM build test result
  NRF52_DK_ARM.txt

• ARMC6 build test result
  NRF52_DK_ARMC6.txt

[MarceloSalazar]

cc @adbridge

[adbridge]

@pan- Please take ownership of this one

[adbridge]

Looks like this may be related #5091

[toyowata]

Fixed in mbed-os-5.6-oob2.