diff --git a/other-licenses/snappy/src/snappy.h b/other-licenses/snappy/src/snappy.h
--- a/other-licenses/snappy/src/snappy.h
+++ b/other-licenses/snappy/src/snappy.h
@@ -60,17 +60,17 @@ namespace snappy {
     // 9 in the future.
     // If you played with other compression algorithms, level 1 is equivalent to
     // fast mode (level 1) of LZ4, level 2 is equivalent to LZ4's level 2 mode
     // and compresses somewhere around zstd:-3 and zstd:-2 but generally with
     // faster decompression speeds than snappy:1 and zstd:-3.
     int level = DefaultCompressionLevel();
 
     constexpr CompressionOptions() = default;
-    constexpr CompressionOptions(int compression_level)
+    constexpr explicit CompressionOptions(int compression_level)
         : level(compression_level) {}
     static constexpr int MinCompressionLevel() { return 1; }
     static constexpr int MaxCompressionLevel() { return 2; }
     static constexpr int DefaultCompressionLevel() { return 1; }
   };
 
   // ------------------------------------------------------------------------
   // Generic compression/decompression routines.