Fixing test builds for devices with softdevices.

[bridadan]

Previously, .hex files were not copied when building source as a library.
This prevents builds that pre-compile source as a library and then includes the build directory as the only source (because there is no softdevice present). This PR adds an option to copy hex files when compiling source as a library. This is currently being used when compiling tests within test.py

Please review @0xc0170 and @screamerbg
FYI @pan-

[0xc0170]

What about static libraries, like there are bootloaders as static libs or just another software that can't be open sourced , but has to be included in the build?

[screamerbg]

Can we copy hex files by default and drop the parameter? This is for library builds after all and do not affect application build.

[bridadan]

I was hesitant to do this because I wasn't sure if the build_library function was used throughout the tools or just in this case. If you're confident this won't cause issues then I'm fine with making it the default behavior.

[sg-]

@bridadan see comments above. Dont modify build lib. its legacy

[bridadan]

@mbed-bot: TEST

HOST_OSES=windows
BUILD_TOOLCHAINS=GCC_ARM,ARM
TARGETS=NRF51822,NRF51_DK

[mbed-bot]

[Build 482]
FAILURE: Something went wrong when building and testing.

[bridadan]

The build bot didn't try and build the tests locally, but I just tried. I'm getting the following linker error when building for the NRF51822 with GCC_ARM for many of the tests:

* NRF51822::GCC_ARM::RTOS_1
        Building project basic (NRF51822, GCC_ARM)
        Link: basic
        C:/Users/bridan01/Documents/dev/mbed/build/mbed/TARGET_NRF51822/TOOLCHAIN_GCC_ARM/NRF51822.ld:133 cannot move location counter backwards (from
 20004330 to 20003800)

@c1728p9 Do you know if this is because the tests are too big to fit in the ROM? I'm not familiar with this error

cc @pan-

[pan-]

@bridadan To makes mbed BLE works with the RTOS work, the main stack size has been changed.
Apparently there is not enough RAM left for the NRF51822, when this test is build.

Let me have a look, maybe it is possible to gain memory from elsewhere.

[sg-]

@bridadan please remove the copy_hex_files=true. I think this was a leftover

[bridadan]

Thanks for the catch! I've updated the commit.

[sg-]

Thanks!! 👍

[screamerbg]

This is still not propagated to Nordic's repository and they cannot use it.

@sg- @pan- @bridadan

[bridadan]

@screamerbg Do we need to resolve this? Or maybe @pan- can help them rebase/update their fork?

[pan-]

@bridadan You don't need do it, I will just cherry-pick your commit.