diff --git a/build/cmake/CMakeLists.txt b/build/cmake/CMakeLists.txt
index 382a2172..0a8513d7 100644
--- a/build/cmake/CMakeLists.txt
+++ b/build/cmake/CMakeLists.txt
@@ -145,6 +145,7 @@ endif()
 include (CheckCCompilerFlag)
 foreach (flag
     # GCC-style
+    -pedantic-errors
     -Wall
     -Wextra
     -Wundef
diff --git a/lib/lz4.c b/lib/lz4.c
index 7d9bd45f..b7dd32a7 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -127,11 +127,11 @@
 #endif  /* _MSC_VER */
 
 #ifndef LZ4_FORCE_INLINE
-#  ifdef _MSC_VER    /* Visual Studio */
+#  if defined (_MSC_VER) && !defined (__clang__)    /* MSVC */
 #    define LZ4_FORCE_INLINE static __forceinline
 #  else
 #    if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
-#      ifdef __GNUC__
+#      if defined (__GNUC__) || defined (__clang__)
 #        define LZ4_FORCE_INLINE static inline __attribute__((always_inline))
 #      else
 #        define LZ4_FORCE_INLINE static inline
diff --git a/lib/xxhash.c b/lib/xxhash.c
index ff28749e..08d8b360 100644
--- a/lib/xxhash.c
+++ b/lib/xxhash.c
@@ -120,12 +120,12 @@ static void* XXH_memcpy(void* dest, const void* src, size_t size) { return memcp
 /* *************************************
 *  Compiler Specific Options
 ***************************************/
-#ifdef _MSC_VER    /* Visual Studio */
+#if defined (_MSC_VER) && !defined (__clang__)    /* MSVC */
 #  pragma warning(disable : 4127)      /* disable: C4127: conditional expression is constant */
 #  define FORCE_INLINE static __forceinline
 #else
 #  if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
-#    ifdef __GNUC__
+#    if defined (__GNUC__) || defined (__clang__)
 #      define FORCE_INLINE static inline __attribute__((always_inline))
 #    else
 #      define FORCE_INLINE static inline