Make the random number generator predictable when fuzzing.

Reviewed-by: Rich Salz <rsalz@openssl.org>
GH: #2023

fuzz/README.md

diff --git a/fuzz/README.md b/fuzz/README.md
index c5a1ba9..d0c30f4 100644
--- a/fuzz/README.md
+++ b/fuzz/README.md
@@ -38,7 +38,8 @@
     $ CC=clang ./config enable-fuzz-libfuzzer \
             --with-fuzzer-include=../../svn-work/Fuzzer \
             --with-fuzzer-lib=../../svn-work/Fuzzer/libFuzzer \
-            -DPEDANTIC enable-asan enable-ubsan no-shared
+            -DPEDANTIC enable-asan enable-ubsan no-shared \
+            -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
     $ sudo apt-get install make
     $ LDCMD=clang++ make -j
     $ fuzz/helper.py $FUZZER