Remove OPENSSL_NO_THREADS.

Uses have been either migrated to
OPENSSL_NO_THREADS_CORRUPT_MEMORY_AND_LEAK_SECRETS_IF_THREADED or removed.

Update-Note: Anything still relying on OPENSSL_NO_THREADS should be updated to
either use OPENSSL_NO_THREADS_CORRUPT_MEMORY_AND_LEAK_SECRETS_IF_THREADED if a
single-threaded-only platform, or fixed to depend on the platform threading
library.

Change-Id: I02ec63bc7ede892bd6463f1a23e2cec70887fab3
Reviewed-on: https://boringssl-review.googlesource.com/c/32744
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/include/openssl/base.h b/include/openssl/base.h
index 5a4bb66..f8567e0 100644
--- a/include/openssl/base.h
+++ b/include/openssl/base.h
@@ -150,15 +150,6 @@
 #define OPENSSL_ANDROID
 #endif
 
-// OPENSSL_NO_THREADS has been deprecated in favor of this much longer and
-// louder name, to better reflect exactly what that option did.
-//
-// TODO(davidben): Remove this block when callers have migrated.
-#if defined(OPENSSL_NO_THREADS) && \
-    !defined(OPENSSL_NO_THREADS_CORRUPT_MEMORY_AND_LEAK_SECRETS_IF_THREADED)
-#define OPENSSL_NO_THREADS_CORRUPT_MEMORY_AND_LEAK_SECRETS_IF_THREADED
-#endif
-
 // BoringSSL requires platform's locking APIs to make internal global state
 // thread-safe, including the PRNG. On some single-threaded embedded platforms,
 // locking APIs may not exist, so this dependency may be disabled with the