Revert "Add -Wl,-z,undefs to Linux linkopts (#90)" (#98)

This reverts commit a29d7774102c5d2e15dbedfaad35845641a1a1d8.

build_defs.bzl

diff --git a/build_defs.bzl b/build_defs.bzl
index 1b10d11..5c88f1c 100644
--- a/build_defs.bzl
+++ b/build_defs.bzl
@@ -68,10 +68,7 @@
         linkopts = linkopts + select({
             "@platforms//os:osx": ["-undefined", "dynamic_lookup"],
             Label("@pybind11//:msvc_compiler"): [],
-            "//conditions:default": [
-                "-Wl,-Bsymbolic",
-                "-Wl,-z,undefs",
-            ],
+            "//conditions:default": ["-Wl,-Bsymbolic"],
         }),
         linkshared = 1,
         tags = tags,