+# Ideally this would be $prefix/lib/modules but default to /lib/modules for compatibility with earlier versions
+AC_ARG_WITH([module_directory],
+ AS_HELP_STRING([--with-module-directory=DIR], [directory in which to look for kernel modules @<:@default=/lib/modules@:>@]),
+ [], [with_module_directory=/lib/modules])
+AC_SUBST([module_directory], [$with_module_directory])
+
+# Check all directory arguments for consistency.
+for ac_var in distconfdir rootlibdir module_directory
+do
+ eval ac_val=\$$ac_var
+ # Remove trailing slashes.
+ case $ac_val in
+ */ )
+ ac_val=`expr "X$ac_val" : 'X\(.*@<:@^/@:>@\)' \| "X$ac_val" : 'X\(.*\)'`
+ eval $ac_var=\$ac_val;;
+ esac
+ # Be sure to have absolute directory names.
+ case $ac_val in
+ @<:@\\/$@:>@* | ?:@<:@\\/@:>@* ) continue;;
+ esac
+ as_fn_error $? "expected an absolute directory name for --$ac_var: $ac_val"
+done
+
+AC_ARG_WITH([zstd],
+ AS_HELP_STRING([--with-zstd], [handle Zstandard-compressed modules @<:@default=disabled@:>@]),
+ [], [with_zstd=no])
+AS_IF([test "x$with_zstd" != "xno"], [
+ PKG_CHECK_MODULES([libzstd], [libzstd >= 1.4.4], [LIBS="$LIBS $libzstd_LIBS"])
+ AC_DEFINE([ENABLE_ZSTD], [1], [Enable Zstandard for modules.])
+ module_compressions="zstd $module_compressions"
+], [
+ AC_MSG_NOTICE([Zstandard support not requested])
+])
+CC_FEATURE_APPEND([with_features], [with_zstd], [ZSTD])
+