!!! existing preserved libs:
>>> package: dev-libs/icu-71.1-r1
 *  - /usr/lib64/libicudata.so.70
 *  - /usr/lib64/libicudata.so.70.1
 *  - /usr/lib64/libicui18n.so.70
 *  - /usr/lib64/libicui18n.so.70.1
 *      used by /usr/bin/js78 (dev-lang/spidermonkey-78.15.0)
 *      used by /usr/lib64/libmozjs-78.so.0.0.0 (dev-lang/spidermonkey-78.15.0)
 *  - /usr/lib64/libicuuc.so.70
 *  - /usr/lib64/libicuuc.so.70.1
 *      used by /usr/bin/js78 (dev-lang/spidermonkey-78.15.0)
 *      used by /usr/lib64/libmozjs-78.so.0.0.0 (dev-lang/spidermonkey-78.15.0)
>>> package: dev-libs/libffi-3.4.2-r1
 *  - /usr/lib64/libffi.so.7
 *  - /usr/lib64/libffi.so.7.1.0
 *      used by /usr/lib/llvm/11/lib64/libLLVM-11.so (sys-devel/llvm-11.1.0)
 *      used by /usr/lib/llvm/12/lib64/libLLVM-12.so (sys-devel/llvm-12.0.1)
 *      used by /usr/lib/llvm/13/lib64/libLLVM-13.so (sys-devel/llvm-13.0.1)
 *      used by /usr/lib/python3.8/lib-dynload/_ctypes.cpython-38-x86_64-linux-gnu.so (dev-lang/python-3.8.9_p2)
Use emerge @preserved-rebuild to rebuild packages using these libraries