Fix buildgo.sh script because of recent changes causing build failures with gcc on linux

[dyung]

Summary

A recent commit ad1466f8cbc520b2f03e1f6daa78f035bccf21df to sanitizer_linux.cpp added code that gcc in C++11 mode cannot handle. Specifically, it added code that included binary literals that gcc in c++11 mode gives an error on. For example, here is the error I get on my local machine:

gotsan.cpp:14071:16: error: missing terminating ' character [-Werror]

case 0b10'010:  // c.lwsp (rd != x0)
         ^

Clang does not give an error on the same code. I found that changing the compiler standard used to c++14 where this is officially supported passes with both gcc and clang, so this should hopefully fix the issue.

[dvyukov]

Thanks!

compiler-rt/lib/tsan/go/buildgo.sh

 
 SRCS="$SRCS $ADD_SRCS"
 
 rm -f $DIR/gotsan.cpp
 for F in $SRCS; do
   cat $F >> $DIR/gotsan.cpp
 done
 
-FLAGS=" -I../rtl -I../.. -I../../sanitizer_common -I../../../include -std=c++11 -Wall -fno-exceptions -fno-rtti -DSANITIZER_GO=1 -DSANITIZER_DEADLOCK_DETECTOR_VERSION=2 $OSCFLAGS $ARCHCFLAGS"
+FLAGS=" -I../rtl -I../.. -I../../sanitizer_common -I../../../include -std=c++14 -Wall -fno-exceptions -fno-rtti -DSANITIZER_GO=1 -DSANITIZER_DEADLOCK_DETECTOR_VERSION=2 $OSCFLAGS $ARCHCFLAGS"
 DEBUG_FLAGS="$FLAGS -DSANITIZER_DEBUG=1 -g"
 FLAGS="$FLAGS -DSANITIZER_DEBUG=0 -O3 -fomit-frame-pointer"
 if [ "$SUFFIX" = "linux_ppc64le" ]; then
   FLAGS="$FLAGS -mcpu=power8 -fno-function-sections"
 elif [ "$SUFFIX" = "linux_amd64" ]; then
   FLAGS="$FLAGS -msse3"
 fi