Compile error when using zsim-nvmain

[cyjseagull]

when I compile zsim-nvmain , error listed below appearanced：

/usr/bin/ld: /usr/lib/librt.a(clock_gettime.o): relocation R_X86_64_32 against `__pthread_clock_gettime' can not be used when making a shared object; recompile with -fPIC

I tried many methods to solve this problem , but failed finally. Can anyone tell me what happend ? The environment was not ready ? Or librt.a had something wrong?