Target an older version of Windows SDK so that we don't get a conflicting definition of struct pollfd

Windows Vista and later SDKs define struct pollfd for WSAPoll(), but it has a permanent bug:
- https://curl.haxx.se/mail/lib-2012-08/0014.html
- https://curl.haxx.se/mail/lib-2012-10/0038.html
civetweb provides its own implementation of poll, but it has a conflicting definition for pollfd.
Hence we block Windows from defining pollfd (which this project doesn't use).
---
 bazel/civetweb.BUILD | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git bazel/civetweb.BUILD bazel/civetweb.BUILD
--- bazel/civetweb.BUILD
+++ bazel/civetweb.BUILD
@@ -9,6 +9,11 @@ config_setting(
     values = {"cpu": "darwin_x86_64"},
 )

+config_setting(
+    name = "darwin_arm64",
+    values = {"cpu": "darwin_arm64"},
+)
+
 config_setting(
     name = "windows",
     values = { "cpu": "x64_windows" },
@@ -34,6 +39,7 @@ cc_library(
         "-DNO_CACHING",
         "-DNO_SSL",
         "-DNO_FILES",
+        "-D_WIN32_WINNT=0x0502",
         "-UDEBUG",
     ],
     includes = [
@@ -46,6 +52,7 @@ cc_library(
     }) + select({
         ":darwin": [],
         ":darwin_x86_64": [],
+        ":darwin_arm64": [],
         ":windows": [],
         ":windows_msvc": [],
         "//conditions:default": ["-lrt"],
@@ -86,6 +93,7 @@ cc_library(
     }) + select({
         ":darwin": [],
         ":darwin_x86_64": [],
+        ":darwin_arm64": [],
         ":windows": [],
         ":windows_msvc": [],
         "//conditions:default": ["-lrt"],
--