diff --git a/lib/zstd_compress.c b/lib/zstd_compress.c
index 6ca31895e..db774ccd8 100644
--- a/lib/zstd_compress.c
+++ b/lib/zstd_compress.c
@@ -1697,7 +1697,7 @@ _storeSequence:
     }
 }
 
-#include "zstd_opt.c"
+#include "zstd_opt.h"
 
 static void ZSTD_compressBlock_opt_bt(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
diff --git a/lib/zstd_opt.c b/lib/zstd_opt.h
similarity index 100%
rename from lib/zstd_opt.c
rename to lib/zstd_opt.h