Remove vestigial line from configure.
diff --git a/configure b/configure
index 1d70ffd..bc3c802 100755
--- a/configure
+++ b/configure
@@ -178,7 +178,6 @@
   cc=${CC}
 fi
 
-cflags=${CFLAGS-"-O3"}
 case "$cc" in
   *gcc*) gcc=1 ;;
   *clang*) gcc=1 ;;