Fix LLVM/MinGW build on Windows.

godot-patches/patch_mingw_build.diff

@@ -226,3 +226,15 @@ index aec331a76c..be98814486 100644
  #include <dispatcherqueue.h>
  #include <windows.foundation.metadata.h>
  #include <windows.ui.composition.h>
+diff --git a/third_party/zlib/cpu_features.c b/third_party/zlib/cpu_features.c
+index 64e0428..1332971 100644
+--- a/third_party/zlib/cpu_features.c
++++ b/third_party/zlib/cpu_features.c
+@@ -11,7 +11,7 @@
+ #include <stdint.h>
+ #if defined(_MSC_VER)
+ #include <intrin.h>
+-#elif defined(ADLER32_SIMD_SSSE3)
++#elif defined(ADLER32_SIMD_SSSE3) || (defined(__clang__) && (defined(__i386__) || defined(__x86_64__)))
+ #include <cpuid.h>
+ #endif

godot-tools/windows.py

@@ -1,3 +1,4 @@
+import os
 import sys
 
 import my_spawn
@@ -7,12 +8,14 @@ from SCons.Variables import *
 
 
 def options(opts):
+    mingw = os.getenv("MINGW_PREFIX", "")
+
     opts.Add(BoolVariable("use_mingw", "Use the MinGW compiler instead of MSVC - only effective on Windows", False))
     opts.Add(BoolVariable("use_clang_cl", "Use the clang driver instead of MSVC - only effective on Windows", False))
     opts.Add(BoolVariable("use_static_cpp", "Link MinGW/MSVC C++ runtime libraries statically", True))
     opts.Add(BoolVariable("debug_crt", "Compile with MSVC's debug CRT (/MDd)", False))
     opts.Add(BoolVariable("use_llvm", "Use the LLVM compiler", False))
-
+    opts.Add("mingw_prefix", "MinGW prefix", mingw)
 
 def exists(env):
     return True
@@ -48,7 +51,7 @@ def generate(env):
             env["CC"] = "clang-cl"
             env["CXX"] = "clang-cl"
 
-    elif sys.platform == "win32" or sys.platform == "msys":
+    elif (sys.platform == "win32" or sys.platform == "msys") and not env["mingw_prefix"]:
         env["use_mingw"] = True
         mingw.generate(env)
         env.Append(CPPDEFINES=["MINGW_ENABLED"])
@@ -63,14 +66,18 @@ def generate(env):
     else:
         env["use_mingw"] = True
         # Cross-compilation using MinGW
+        prefix = ""
+        if env["mingw_prefix"]:
+            prefix = env["mingw_prefix"] + "/bin/"
+
         if env["arch"] == "x86_64":
-            prefix = "x86_64"
+            prefix += "x86_64"
         elif env["arch"] == "arm64":
-            prefix = "aarch64"
+            prefix += "aarch64"
         elif env["arch"] == "arm32":
-            prefix = "armv7"
+            prefix += "armv7"
         elif env["arch"] == "x86_32":
-            prefix = "i686"
+            prefix += "i686"
 
         if env["use_llvm"]:
             env["CXX"] = prefix + "-w64-mingw32-clang++"
@@ -100,3 +107,6 @@ def generate(env):
                 "-Wl,--no-undefined",
             ]
         )
+
+        if (sys.platform == "win32" or sys.platform == "msys"):
+            my_spawn.configure(env)