Index: ObsoleteFiles.inc
===================================================================
--- ObsoleteFiles.inc
+++ ObsoleteFiles.inc
@@ -40,6 +40,9 @@
 #   xargs -n1 | sort | uniq -d;
 # done
 
+# 2021xxxx libc++ moved to /lib
+OLD_LIBS+=usr/lib/libc++.so.1
+
 # 20211125 Old SCSI drivers removed
 OLD_FILES+=usr/share/man/man4/amr.4.gz
 OLD_FILES+=usr/share/man/man4/esp.4.gz
Index: lib/libc++/Makefile
===================================================================
--- lib/libc++/Makefile
+++ lib/libc++/Makefile
@@ -3,6 +3,7 @@
 .include <src.opts.mk>
 
 PACKAGE=	clibs
+SHLIBDIR?=	/lib
 _LIBCXXRTDIR=	${SRCTOP}/contrib/libcxxrt
 HDRDIR=		${SRCTOP}/contrib/llvm-project/libcxx/include
 SRCDIR=		${SRCTOP}/contrib/llvm-project/libcxx/src