diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -155,6 +155,7 @@
 
 TGTS=	all all-man buildenv buildenvvars buildetc buildkernel buildworld \
 	check check-old check-old-dirs check-old-files check-old-libs \
+	check-symbols \
 	checkdpadd checkworld clean cleandepend cleandir cleankernel \
 	cleanworld cleanuniverse \
 	delete-old delete-old-dirs delete-old-files delete-old-libs \
diff --git a/share/mk/bsd.lib.mk b/share/mk/bsd.lib.mk
--- a/share/mk/bsd.lib.mk
+++ b/share/mk/bsd.lib.mk
@@ -375,6 +375,39 @@
 ${SHLIB_NAME}.debug: ${SHLIB_NAME_FULL}
 	${OBJCOPY} --only-keep-debug ${SHLIB_NAME_FULL} ${.TARGET}
 .endif
+
+_SYMLIST?=${SRCTOP}/tools/build/symlist.awk
+.if exists(${_SYMLIST}) && !target(${SHLIB_NAME}.symbols)
+CLEANFILES+= ${SHLIB_NAME}.symbols
+${SHLIB_NAME}.symbols: ${SHLIB_NAME_FULL} ${_SYMLIST}
+	(printf "%sgenerated by bsd.lib.mk\n" @; \
+	 readelf -sW ${.ALLSRC:[1]} | awk -f ${_SYMLIST} | sort ) > ${.TARGET}
+
+.if defined(SYMBOLS_REF_MD)
+_SYMBOLS_REF_ARCH= -${MACHINE_ARCH}
+.else
+_SYMBOLS_REF_ARCH=
+.endif
+SYMBOLS_REF?=	${.CURDIR}/.symref${_SYMBOLS_REF_ARCH}
+.if make(check-symbols) && ${.MAKE.LEVEL} == 1
+_CHECK_SYMBOLS_WARNING?= echo
+.else
+_CHECK_SYMBOLS_WARNING?= true
+.endif
+check-symbols: ${SHLIB_NAME}.symbols
+	@if [ ! -e ${SYMBOLS_REF} ]; then \
+		${_CHECK_SYMBOLS_WARNING} "WARNING: no symbol reference (${SYMBOLS_REF:T}), run 'make update-symref'" 1>&2; \
+	else \
+		if ! diff ${SYMBOLS_REF} ${SHLIB_NAME}.symbols; then \
+			echo "ERROR: symbol set changed, correct or run 'make update-symref'" 1>&2; \
+			false; \
+		fi \
+	fi
+
+update-symref: ${SHLIB_NAME}.symbols
+	cp ${SHLIB_NAME}.symbols ${SYMBOLS_REF}
+.endif #exists(${_SYMLIST}) && !target(${SHLIB_NAME}.symbols)
+
 .endif #defined(SHLIB_NAME)
 
 .if defined(INSTALL_PIC_ARCHIVE) && defined(LIB) && !empty(LIB)
diff --git a/share/mk/bsd.subdir.mk b/share/mk/bsd.subdir.mk
--- a/share/mk/bsd.subdir.mk
+++ b/share/mk/bsd.subdir.mk
@@ -41,7 +41,8 @@
 
 SUBDIR_TARGETS+= \
 		all all-man analyze buildconfig buildfiles buildincludes \
-		checkdpadd clean cleandepend cleandir cleanilinks \
+		checkdpadd check-symbols \
+		clean cleandepend cleandir cleanilinks \
 		cleanobj depend distribute files includes installconfig \
 		installdirs \
 		installfiles installincludes print-dir realinstall \
diff --git a/tools/build/symlist.awk b/tools/build/symlist.awk
new file mode 100644
--- /dev/null
+++ b/tools/build/symlist.awk
@@ -0,0 +1,61 @@
+#-
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2024 SRI International
+#
+# This software was developed by SRI International, the University of
+# Cambridge Computer Laboratory (Department of Computer Science and
+# Technology), and Capabilities Limited under Defense Advanced Research
+# Projects Agency (DARPA) Contract No. FA8750-24-C-B047 ("DEC").
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+# symlist.awk - process "readelf -sW" output to produce compat symbol list
+
+BEGIN {
+	symtab = ""
+}
+
+/^Symbol table / {
+	symtab = $3
+	gsub(/'/, "", symtab)
+}
+
+/^ *[0-9]+:/ {
+	# We don't (currently) care what symbols the library depends on
+	if ($7 == "UND") next
+
+	# Don't track symbols in the private namespace.  Instead, depend
+	# on linking with --no-undefined-version to detect dropped symbols.
+	if ($8 ~ /@FBSDprivate_/) next
+
+	# Only print symbols from .dynsym.  Unstriped libraries may have
+	# internal symbol tables and we can't rely on readelf supporting
+	# -D (llvm-readelf doesn't).
+	if (symtab != ".dynsym") next
+
+	# readelf -sW header:
+	#    Num:    Value          Size Type    Bind   Vis      Ndx Name
+	#    1       2              3    4       5      6        7   8
+	print $8 " " tolower($4) " " tolower($5) " " tolower($6)
+}