--- /dev/null
+glibc-2.28 did hide loff_t indef system-specific macros:
+ https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=663e7d784977f6b15c0cab73f754f9f39c9c0c2c
+
+This caused build failure:
+ ../include/reiserfs_lib.h:300:55: error: unknown type name 'loff_t'; did you mean 'off_t'?
+
+Re-enable extensions to pull loff_t back.
+
+https://bugs.gentoo.org/663930
+--- a/configure.ac
++++ b/configure.ac
+@@ -23,2 +23,4 @@ AC_PROG_MAKE_SET
+ AC_PROG_LIBTOOL
++dnl pull in loff_t from glibc
++AC_USE_SYSTEM_EXTENSIONS
+