Undefined reference to `atexit'

[Matzz]

Hi,
Im trying to use static variables inside function. But I'm getting undefined reference to atexit.
My code:

#include <user_config.h>
#include <SmingCore/SmingCore.h>
class Test {
    public:
        static Test& getInstance() {
            static Test injector = Test();
            return injector;
        }
        String a = "";
};

void init() {
    Test::getInstance();
}

Log:

23:15:50 **** Build of configuration Sming for project Abc ****
make all 
OC out/build/libmain2.a
make -C /C/tools/sming/Sming/rboot
make[1]: Entering directory `/C/tools/sming/Sming/rboot'
CC rboot-stage2a.c
LD /c/Users/Matzz/sming.examples/Abc/out/build/rboot-stage2a.elf
E2 /c/Users/Matzz/sming.examples/Abc/out/build/rboot-hex2a.h
CC rboot.c
LD /c/Users/Matzz/sming.examples/Abc/out/build/rboot.elf
E2 /c/Users/Matzz/sming.examples/Abc/out/firmware/rboot.bin
make[1]: Leaving directory `/C/tools/sming/Sming/rboot'
C+ app/application.cpp
CC /C/tools/sming/Sming/rboot/appcode/rboot-api.c
CC /C/tools/sming/Sming/rboot/appcode/rboot-bigflash.c
AR out/build/app_app.a
LD out/build/app_0.out
out/build/app_app.a(application.o):(.text._Z4initv+0x10): undefined reference to `atexit'
out/build/app_app.a(application.o): In function `_ZN4TestC4Ev':
C:\Users\Matzz\sming.examples\Abc/app/application.cpp:3: undefined reference to `atexit'
collect2.exe: error: ld returned 1 exit status
make: *** [out/build/app_0.out] Error 1

23:16:39 Build Finished (took 48s.537ms)

What is interesting removing String a from Test class solves the problem.
Related issue in arduino project - arduino/Arduino#2229

[hreintke]

@Matzz :
Can you submit a PR to solve this in SmingRTOS.
Will close this issue in SmingNONOS