-test "$shared" = "no" || {
-# Disable dynamic linking if ld is broken and can't do -Bsymbolic-functions
-LDFLAGS_DUMMY=
-tryldflag LDFLAGS_DUMMY -Wl,-Bsymbolic-functions || {
-test "$shared" = "yes" && fail "$0: error: linker cannot build shared library"
-printf "warning: disabling dynamic linking support\n"
-shared=no
-}
-}
+# Prevent linking if there are undefined symbols; if any exist,
+# libc.so will crash at runtime during relocation processing.
+# The common way this can happen is failure to link the compiler
+# runtime library; implementation error is also a possibility.
+tryldflag LDFLAGS_AUTO -Wl,--no-undefined
+
+# Avoid exporting symbols from compiler runtime libraries. They
+# should be hidden anyway, but some toolchains including old gcc
+# versions built without shared library support and pcc are broken.
+tryldflag LDFLAGS_AUTO -Wl,--exclude-libs=ALL
+
+# Linking with -Bsymbolic-functions is no longer mandatory for
+# the dynamic linker to work, but enable it if it works as
+# a linking optimization.
+tryldflag LDFLAGS_AUTO -Wl,-Bsymbolic-functions