CheckFunctionExists undefined reference to `pthread_create'
I build https://github.com/alexa/avs-device-sdk in buildroot , gcc: gcc-linaro-4.9.4-2017.01-x86_64_arm-linux-gnueabihf wrong: arm/gcc-linaro-4.9.4-2017.01-x86_64_arm-linux-gnueabihf/bin/../lib/gcc/arm-linux-gnueabihf/4.9.4/../../../../arm-linux-gnueabihf/bin/ld: cannot find -lpthreads
CMakeFiles/cmTC_c0935.dir/CheckSymbolExists.c.o: In function main': CheckSymbolExists.c:(.text+0x1c): undefined reference to
pthread_create'
CheckSymbolExists.c:(.text+0x20): undefined reference to `pthread_create'
please help ! thanks!