Improve brotli windows patch

Author: fhanau

build/BUILD.brotli

@@ -1,8 +1,6 @@
 # Description:
 #   Brotli is a generic-purpose lossless compression algorithm.
 
-# Build file is the same as in brotli, but with STRICT_C_OPTIONS disabled as elaborated below.
-
 load(":compiler_config_setting.bzl", "create_msvc_config")
 
 package(
@@ -43,24 +41,41 @@ config_setting(
     visibility = ["//visibility:public"],
 )
 
+config_setting(
+    name = "clang-cl",
+    values = {"compiler": "clang-cl"},
+    visibility = ["//visibility:public"],
+)
+
 create_msvc_config()
 
-# Disable strict C options, rely on workerd-level warnings instead
 STRICT_C_OPTIONS = select({
     ":msvc": [],
+    ":clang-cl": [
+        "/W4",
+        "-Wconversion",
+        "-Werror",
+        "-Wextra",
+        "-Wlong-long",
+        "-Wmissing-declarations",
+        "-Wmissing-prototypes",
+        "-Wno-strict-aliasing",
+        "-Wshadow",
+        "-Wsign-compare",
+        "-Wno-sign-conversion",
+    ],
     "//conditions:default": [
-        # clang-cl does not support --pedantic-errors
-        # "--pedantic-errors",
-        # "-Wall",
-        # "-Wconversion",
-        # "-Werror",
-        # "-Wextra",
-        # "-Wlong-long",
-        # "-Wmissing-declarations",
-        # "-Wmissing-prototypes",
-        # "-Wno-strict-aliasing",
-        # "-Wshadow",
-        # "-Wsign-compare",
+        "--pedantic-errors",
+        "-Wall",
+        "-Wconversion",
+        "-Werror",
+        "-Wextra",
+        "-Wlong-long",
+        "-Wmissing-declarations",
+        "-Wmissing-prototypes",
+        "-Wno-strict-aliasing",
+        "-Wshadow",
+        "-Wsign-compare",
     ],
 })
 
@@ -128,6 +143,7 @@ cc_library(
     hdrs = [":enc_headers"],
     copts = STRICT_C_OPTIONS,
     linkopts = select({
+        ":clang-cl": [],
         ":msvc": [],
         "//conditions:default": ["-lm"],
     }),