diff --git a/BUILDING.md b/BUILDING.md
index f915d8564..742d454c7 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -30,11 +30,11 @@ most recent stable version of each tool.
     by CMake, it may be configured explicitly by setting
     `CMAKE_ASM_NASM_COMPILER`.
 
-  * C and C++ compilers with C++14 support are required. If using a C compiler
-    other than MSVC, C11 support is also requried. On Windows, MSVC from
-    Visual Studio 2019 or later with Windows 10 SDK 2104 or later are supported,
-    but using the latest versions is recommended. Recent versions of GCC (6.1+)
-    and Clang should work on non-Windows platforms, and maybe on Windows too.
+  * Compilers for C11 and C++14, or later, are required. On Windows, MSVC from
+    Visual Studio 2019 or later with Windows 10 SDK 2104 or later are
+    supported, but using the latest versions is recommended. Recent versions of
+    GCC (6.1+) and Clang should work on non-Windows platforms, and maybe on
+    Windows too.
 
   * The most recent stable version of [Go](https://golang.org/dl/) is required.
     Note Go is exempt from the five year support window. If not found by CMake,
diff --git a/crypto/internal.h b/crypto/internal.h
index a2c49d6c0..4de4597de 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -127,24 +127,13 @@
 #endif
 
 #if !defined(__cplusplus)
-#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
-#include <stdalign.h>
-#elif defined(_MSC_VER) && !defined(__clang__)
-#define alignas(x) __declspec(align(x))
-#define alignof __alignof
-#else
-// With the exception of MSVC, we require C11 to build the library. C11 is a
-// prerequisite for improved refcounting performance. All our supported C
-// compilers have long implemented C11 and made it default. The most likely
-// cause of pre-C11 modes is stale -std=c99 or -std=gnu99 flags in build
-// configuration. Such flags can be removed.
-//
-// TODO(davidben): In MSVC 2019 16.8 or higher (_MSC_VER >= 1928),
-// |__STDC_VERSION__| will be 201112 when passed /std:c11 and unset otherwise.
-// C11 alignas and alignof are only implemented in C11 mode. Can we mandate C11
-// mode for those versions?
+#if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
+// BoringSSL requires C11 to build the library. The most likely cause of
+// pre-C11 modes is stale -std=c99 or -std=gnu99 flags in build configuration.
+// Such flags can be removed. If building with MSVC, build with /std:c11.
 #error "BoringSSL must be built in C11 mode or higher."
 #endif
+#include <stdalign.h>
 #endif
 
 #if defined(OPENSSL_THREADS) && \
@@ -160,9 +149,8 @@
 
 // Determine the atomics implementation to use with C.
 #if !defined(__cplusplus)
-#if !defined(OPENSSL_C11_ATOMIC) && defined(OPENSSL_THREADS) &&   \
-    !defined(__STDC_NO_ATOMICS__) && defined(__STDC_VERSION__) && \
-    __STDC_VERSION__ >= 201112L
+#if !defined(OPENSSL_C11_ATOMIC) && defined(OPENSSL_THREADS) && \
+    !defined(__STDC_NO_ATOMICS__)
 #define OPENSSL_C11_ATOMIC
 #endif