d:/program files (x86)/gnu tools arm embedded/7 2018-q2-update/bin/../lib/gcc/arm-none-eabi/7.3.1/../../../../arm-none-eabi/lib/thumb/v7-m\libc_nano.a(lib_a-abort.o): In function `abort':
abort.c:(.text.abort+0xa): undefined reference to `_exit'
d:/program files (x86)/gnu tools arm embedded/7 2018-q2-update/bin/../lib/gcc/arm-none-eabi/7.3.1/../../../../arm-none-eabi/lib/thumb/v7-m\libc_nano.a(lib_a-signalr.o): In function `_kill_r':
signalr.c:(.text._kill_r+0xe): undefined reference to `_kill'
d:/program files (x86)/gnu tools arm embedded/7 2018-q2-update/bin/../lib/gcc/arm-none-eabi/7.3.1/../../../../arm-none-eabi/lib/thumb/v7-m\libc_nano.a(lib_a-signalr.o): In function `_getpid_r':
signalr.c:(.text._getpid_r+0x0): undefined reference to `_getpid'