diff --git a/configure.ac b/configure.ac
index 53d4c6ffa..76374e4b5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -430,6 +430,7 @@ RB_CHK_SYSHEADER([mutex],          [MUTEX])
 RB_CHK_SYSHEADER([shared_mutex],   [SHARED_MUTEX])
 RB_CHK_SYSHEADER([condition_variable], [CONDITION_VARIABLE])
 RB_CHK_SYSHEADER([random],         [RANDOM])
+RB_CHK_SYSHEADER([bitset],         [BITSET])
 
 dnl experimental
 RB_CHK_SYSHEADER([string_view],                 [STRING_VIEW])
diff --git a/include/ircd/stdinc.h b/include/ircd/stdinc.h
index a5a509d2d..63da37a92 100644
--- a/include/ircd/stdinc.h
+++ b/include/ircd/stdinc.h
@@ -116,6 +116,7 @@ extern "C" {
 #include <RB_INC_SHARED_MUTEX
 #include <RB_INC_CONDITION_VARIABLE
 #include <RB_INC_RANDOM
+#include <RB_INC_BITSET
 
 ///////////////////////////////////////////////////////////////////////////////
 //