lib/crypto/MD5: add option to use libavutil instead of libgcrypt

src/lib/crypto/MD5.cxx

@@ -28,20 +28,38 @@
  */
 
 #include "MD5.hxx"
+#include "util/HexFormat.hxx"
+#include "config.h"
+
+#ifdef HAVE_LIBAVUTIL
+extern "C" {
+#include <libavutil/md5.h>
+}
+#else
 #include "lib/gcrypt/MD5.hxx"
 #include "lib/gcrypt/Init.hxx"
-#include "util/HexFormat.hxx"
+#endif
 
 void
 GlobalInitMD5() noexcept
 {
+#ifdef HAVE_LIBAVUTIL
+	/* no initialization necessary */
+#else
 	Gcrypt::Init();
+#endif
 }
 
 std::array<uint8_t, 16>
 MD5(ConstBuffer<void> input) noexcept
 {
+#ifdef HAVE_LIBAVUTIL
+	std::array<uint8_t, 16> result;
+	av_md5_sum(&result.front(), (const uint8_t *)input.data, input.size);
+	return result;
+#else
 	return Gcrypt::MD5(input);
+#endif
 }
 
 StringBuffer<33>

src/lib/crypto/meson.build

@@ -1,9 +1,10 @@
-if gcrypt_dep.found()
+if libavutil_dep.found() or gcrypt_dep.found()
   crypto_md5 = static_library(
     'crypto_md5',
     'MD5.cxx',
     include_directories: inc,
     dependencies: [
+      libavutil_dep,
       gcrypt_dep,
     ],
   )