--- a/third_party/grpc/src/core/lib/gpr/log_linux.cc.ORIG	1980-01-01 00:00:00.000000000 +0100
+++ a/third_party/grpc/src/core/lib/gpr/log_linux.cc.ORIG	2019-09-17 13:50:17.166911668 +0200
@@ -40,7 +40,9 @@ 
 #include <time.h>
 #include <unistd.h>
 
+/* contained in unistd.h 
 static long gettid(void) { return syscall(__NR_gettid); }
+*/
 
 void gpr_log(const char* file, int line, gpr_log_severity severity,
              const char* format, ...) {