diff --git a/common/xash3d_types.h b/common/xash3d_types.h
index 1575eafd..3ce4e612 100644
--- a/common/xash3d_types.h
+++ b/common/xash3d_types.h
@@ -128,6 +128,14 @@ typedef uint64_t longtime_t;
 	#define STATIC_ASSERT( x, y ) STATIC_ASSERT_2( __LINE__, x, y )
 #endif
 
+#if !defined( __cplusplus ) && __STDC_VERSION__ >= 199101L // not C++ and C99 or newer
+	#define XASH_RESTRICT restrict
+#elif _MSC_VER || __GNUC__ || __clang__ // compiler-specific extensions
+	#define XASH_RESTRICT __restrict
+#else
+	#define XASH_RESTRICT // nothing
+#endif
+
 #ifdef XASH_BIG_ENDIAN
 #define LittleLong(x) (((int)(((x)&255)<<24)) + ((int)((((x)>>8)&255)<<16)) + ((int)(((x)>>16)&255)<<8) + (((x) >> 24)&255))
 #define LittleLongSW(x) (x = LittleLong(x) )
diff --git a/public/crtlib.c b/public/crtlib.c
index cb066df0..b8545aa1 100644
--- a/public/crtlib.c
+++ b/public/crtlib.c
@@ -274,6 +274,13 @@ const byte *Q_memmem( const byte *haystack, size_t haystacklen, const byte *need
 	return NULL;
 }
 
+void Q_memor( byte *XASH_RESTRICT dst, const byte *XASH_RESTRICT src, size_t len )
+{
+	size_t i;
+	for( i = 0; i < len; i++ ) // msvc likes to optimize this loop form
+		dst[i] |= src[i];
+}
+
 const char* Q_timestamp( int format )
 {
 	static string	timestamp;
diff --git a/public/crtlib.h b/public/crtlib.h
index ad9d345c..d03f308a 100644
--- a/public/crtlib.h
+++ b/public/crtlib.h
@@ -45,6 +45,10 @@ enum
 #define PFILE_TOKEN_MAX_LENGTH 1024
 #define PFILE_FS_TOKEN_MAX_LENGTH 512
 
+#ifdef __cplusplus
+#define restrict
+#endif // __cplusplus
+
 //
 // build.c
 //
@@ -72,6 +76,7 @@ void Q_atov( float *vec, const char *str, size_t siz );
 qboolean Q_stricmpext( const char *pattern, const char *text );
 qboolean Q_strnicmpext( const char *pattern, const char *text, size_t minimumlen );
 const byte *Q_memmem( const byte *haystack, size_t haystacklen, const byte *needle, size_t needlelen );
+void Q_memor( byte *XASH_RESTRICT dst, const byte *XASH_RESTRICT src, size_t len );
 const char *Q_timestamp( int format );
 int Q_vsnprintf( char *buffer, size_t buffersize, const char *format, va_list args );
 int Q_snprintf( char *buffer, size_t buffersize, const char *format, ... ) _format( 3 );