this only happen in Go 1.5
package runtime: C source files not allowed when not using cgo or SWIG: atomic_386.c defs.c float.c heapdump.c lfstack.c malloc.c mcache.c mcentral.c mem_linux.c mfixalloc.c mgc0.c mheap.c msize.c os_linux.c os_linux_386.c panic.c parfor.c proc.c runtime.c signal.c signal_386.c signal_unix.c stack.c string.c sys_x86.c vlrt.c
this only happen in Go 1.5
package runtime: C source files not allowed when not using cgo or SWIG: atomic_386.c defs.c float.c heapdump.c lfstack.c malloc.c mcache.c mcentral.c mem_linux.c mfixalloc.c mgc0.c mheap.c msize.c os_linux.c os_linux_386.c panic.c parfor.c proc.c runtime.c signal.c signal_386.c signal_unix.c stack.c string.c sys_x86.c vlrt.c