work around toolchains with broken visibility in libgcc/libpcc
diff --git a/configure b/configure
index dece1d0..ee21771 100755
--- a/configure
+++ b/configure
@@ -534,6 +534,11 @@
# 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
+
test "$shared" = "no" || {
# Disable dynamic linking if ld is broken and can't do -Bsymbolic-functions
LDFLAGS_DUMMY=