diff --git a/mfbt/Compression.cpp b/mfbt/Compression.cpp
index c675aa90af62..830e0b01b43b 100644
--- a/mfbt/Compression.cpp
+++ b/mfbt/Compression.cpp
@@ -12,27 +12,10 @@
 // corecrt_memory.h.
 #include <string>
 
-// Because we wrap lz4.c in an anonymous namespace, all of its #includes
-// go in the anonymous namespace too. This would create conflicting
-// declarations for intrinsic functions that are internally defined
-// at top-level. Including intrin.h here prevents it from being included
-// later within the anonymous namespace.
-#ifdef _MSC_VER
-#include <intrin.h>
-#endif
+#include "lz4.h"
 
 using namespace mozilla::Compression;
 
-namespace {
-
-extern "C" {
-
-#include "lz4.c"
-
-}
-
-}/* anonymous namespace */
-
 /* Our wrappers */
 
 size_t
diff --git a/mfbt/lz4.h b/mfbt/lz4.h
index 020a09d5bd50..5a5de84c31ef 100644
--- a/mfbt/lz4.h
+++ b/mfbt/lz4.h
@@ -72,19 +72,23 @@ extern "C" {
 /*
 *  LZ4_DLL_EXPORT :
 *  Enable exporting of functions when building a Windows DLL
-*  LZ4LIB_API :
+*  LZ4LIB_VISIBILITY :
 *  Control library symbols visibility.
 */
-#if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
-#  define LZ4LIB_API __declspec(dllexport)
-#elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
-#  define LZ4LIB_API __declspec(dllimport) /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
-#elif defined(__GNUC__) && (__GNUC__ >= 4)
-#  define LZ4LIB_API __attribute__ ((__visibility__ ("default")))
-#else
-#  define LZ4LIB_API
+#ifndef LZ4LIB_VISIBILITY
+#  if defined(__GNUC__) && (__GNUC__ >= 4)
+#    define LZ4LIB_VISIBILITY __attribute__ ((visibility ("default")))
+#  else
+#    define LZ4LIB_VISIBILITY
+#  endif
+#endif
+#if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
+#  define LZ4LIB_API __declspec(dllexport) LZ4LIB_VISIBILITY
+#elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
+#  define LZ4LIB_API __declspec(dllimport) LZ4LIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
+#else
+#  define LZ4LIB_API LZ4LIB_VISIBILITY
 #endif
-
 
 /*------   Version   ------*/
 #define LZ4_VERSION_MAJOR    1    /* for breaking interface changes  */
diff --git a/mfbt/moz.build b/mfbt/moz.build
index 6c90106384bf..4e1aee1d87ea 100644
--- a/mfbt/moz.build
+++ b/mfbt/moz.build
@@ -147,24 +147,16 @@ DEFINES['IMPL_MFBT'] = True
 SOURCES += [
     'Compression.cpp',
     'decimal/Decimal.cpp',
+    'lz4.c',
 ]
 
 DisableStlWrapping()
 
-# Suppress warnings in third-party LZ4 code.
-# TODO: Remove these suppressions after bug 993267 is fixed.
-
-if CONFIG['GNU_CXX']:
-    SOURCES['Compression.cpp'].flags += ['-Wno-unused-function']
-    CXXFLAGS += ['-Wno-error=shadow']
-
 if CONFIG['CLANG_CXX']:
     # Suppress warnings from third-party V8 Decimal code.
     SOURCES['decimal/Decimal.cpp'].flags += ['-Wno-implicit-fallthrough']
 
-if CONFIG['_MSC_VER']:
-    # Error 4804 is "'>' : unsafe use of type 'bool' in operation"
-    SOURCES['Compression.cpp'].flags += ['-wd4804']
-
 if CONFIG['MOZ_NEEDS_LIBATOMIC']:
     OS_LIBS += ['atomic']
+
+DEFINES['LZ4LIB_VISIBILITY'] = ''