diff --git a/src/_cffi_src/build_openssl.py b/src/_cffi_src/build_openssl.py
index 35ccd6b..6d5ee4c 100755
--- a/src/_cffi_src/build_openssl.py
+++ b/src/_cffi_src/build_openssl.py
@@ -42,10 +42,7 @@ def _get_openssl_libraries(platform):
         # -lpthread required due to usage of pthread an potential
         # existance of a static part containing e.g. pthread_atfork
         # (https://github.com/pyca/cryptography/issues/5084)
-        if sys.platform == "zos":
-            return ["ssl", "crypto"]
-        else:
-            return ["ssl", "crypto", "pthread"]
+        return ["ssl", "crypto"]
 
 
 def _extra_compile_args(platform):