build: Skip warning flags for zlib on Windows

Author: varungandhi-src

third_party/zlib.BUILD

@@ -55,13 +55,15 @@ cc_library(
         # but clients generally use <>.
     ] + _ZLIB_PUBLIC_HEADERS,
     hdrs = _ZLIB_PREFIXED_HEADERS,
-    copts = [
+    copts = select({
+      "@platforms//os:windows": [],
+      "//conditions:default": [
         "-Wno-unused-variable",
         "-Wno-implicit-function-declaration",
         "-Wno-implicit-fallthrough",
         "-Wno-cast-qual",
         "-Wno-covered-switch-default",
         "-Wno-deprecated-non-prototype",
-    ],
+    ]}),
     includes = ["zlib/include/"],
 )