diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
--- a/share/mk/bsd.sys.mk
+++ b/share/mk/bsd.sys.mk
@@ -217,6 +217,14 @@
 .endif
 .endif
 
+# GCC 12.1.0
+.if ${COMPILER_VERSION} >= 120100
+# These warnings are raised by headers in libc++ so are disabled
+# globally for all C++
+CXXWARNFLAGS+=	-Wno-literal-suffix 			\
+		-Wno-error=unknown-pragmas
+.endif
+
 # GCC produces false positives for functions that switch on an
 # enum (GCC bug 87950)
 CWARNFLAGS+=	-Wno-return-type