fi
AM_CONDITIONAL([ENABLE_SSSE3_SHA1], [test "$ENABLE_SSSE3_SHA1" = "yes"])
+# --------------------------- Zstandard support -------------------------------
+
+AC_MSG_CHECKING([whether to include support for Zstandard compression])
+AC_ARG_WITH([zstd],
+ [AS_HELP_STRING([--with-zstd],
+ [Zstandard compression support via libzstd
+ (EXPERIMENTAL)])],
+ [WITH_ZSTD=$withval],
+ [WITH_ZSTD=no])
+AC_MSG_RESULT([$WITH_ZSTD])
+
+if test "$WITH_ZSTD" = "yes" ; then
+ PKG_CHECK_MODULES([LIBZSTD], [libzstd], [],
+ [AC_MSG_ERROR([Cannot find libzstd! Either install libzstd, or
+ configure --without-zstd to disable Zstandard compression
+ support.])])
+ PKGCONFIG_PRIVATE_REQUIRES="$PKGCONFIG_PRIVATE_REQUIRES zstd"
+ AC_DEFINE([WITH_ZSTD], [1], [Define to 1 if using Zstandard support])
+fi
+AM_CONDITIONAL([WITH_ZSTD], [test "$WITH_ZSTD" = "yes"])
+
# ----------------------------- Other options ---------------------------------
AC_MSG_CHECKING([whether to include error messages])