Revert changes to configure

Author: thisisnic

r/configure

@@ -407,11 +407,6 @@ else
   echo "*** Failed to find Arrow C++ libraries."
 fi
 
-# If using Clang, suppress GNU variadic macro warning from Thrift
-#if ${R_HOME}/bin/R CMD config CXX | grep -q clang; then
-#  PKG_CFLAGS="$PKG_CFLAGS -Wno-gnu-zero-variadic-macro-arguments"
-#fi
-
 # Test that we can compile something with those flags
 CXX17="`${R_HOME}/bin/R CMD config CXX17` -E"
 CXX17FLAGS=`"${R_HOME}"/bin/R CMD config CXX17FLAGS`