diff --git a/erlang/apps/lib/include/pdp10_elf36.hrl b/erlang/apps/lib/include/pdp10_elf36.hrl
index 4e9f262..08ed8cb 100644
--- a/erlang/apps/lib/include/pdp10_elf36.hrl
+++ b/erlang/apps/lib/include/pdp10_elf36.hrl
@@ -1565,6 +1565,7 @@
 -define(AT_BASE_PLATFORM, 24).          % String identifying real platform,
                                         % may differ from AT_PLATFORM.
 -define(AT_RANDOM,      25).            % Address of 16 random bytes.
+-define(AT_HWCAP2,      26).            % Extension of AT_HWCAP.
 -define(AT_RSEQ_FEATURE_SIZE, 27).      % rseq supported feature size
 -define(AT_RSEQ_ALIGN,  28).            % rseq allocation alignment
 -define(AT_EXECFN,      31).            % Filename of executable.