diff --git a/lib/libpmc/Makefile b/lib/libpmc/Makefile
--- a/lib/libpmc/Makefile
+++ b/lib/libpmc/Makefile
@@ -46,9 +46,6 @@
 CFLAGS+= -I${.CURDIR} -I${SRCTOP}/sys
 CWARNFLAGS.gcc+= -Wno-shadow -Wno-cast-align
 
-# Silence warnings about usage of deprecated std::auto_ptr
-CXXWARNFLAGS+=	-Wno-deprecated-declarations
-
 MAN=	pmc.3
 MAN+=	pmc_allocate.3
 MAN+=	pmc_attach.3