diff --git a/configure.ac b/configure.ac
index f2e5dcc83..2bddac390 100644
--- a/configure.ac
+++ b/configure.ac
@@ -917,6 +917,7 @@ RB_CHK_SYSHEADER(unordered_map, [UNORDERED_MAP])
 RB_CHK_SYSHEADER(string, [STRING])
 RB_CHK_SYSHEADER(cstring, [CSTRING])
 RB_CHK_SYSHEADER(locale, [LOCALE])
+RB_CHK_SYSHEADER(cuchar, [CUCHAR])
 RB_CHK_SYSHEADER(codecvt, [CODECVT])
 RB_CHK_SYSHEADER(sstream, [SSTREAM])
 RB_CHK_SYSHEADER(fstream, [FSTREAM])
diff --git a/include/ircd/stdinc.h b/include/ircd/stdinc.h
index 6e40d45b1..7e4354252 100644
--- a/include/ircd/stdinc.h
+++ b/include/ircd/stdinc.h
@@ -67,6 +67,7 @@ extern "C"
 #include <RB_INC_STRING
 #include <RB_INC_CSTRING
 #include <RB_INC_STRING_VIEW
+#include <RB_INC_CUCHAR
 #include <RB_INC_LOCALE
 #include <RB_INC_CODECVT
 #include <RB_INC_MAP