mingw: define _WIN32_WINNT when building CRT

src/Compilation.zig

@@ -5205,22 +5205,21 @@ pub fn addCCArgs(
         } else if (target.isMinGW()) {
             try argv.append("-D__MSVCRT_VERSION__=0xE00"); // use ucrt
 
+            switch (ext) {
+                .c, .cpp, .m, .mm, .h, .hpp, .hm, .hmm, .cu, .rc, .assembly, .assembly_with_cpp => {
+                    const minver: u16 = @truncate(@intFromEnum(target.os.getVersionRange().windows.min) >> 16);
+                    try argv.append(
+                        try std.fmt.allocPrint(arena, "-D_WIN32_WINNT=0x{x:0>4}", .{minver}),
+                    );
+                },
+                else => {},
+            }
         }
     }
 
     const llvm_triple = try @import("codegen/llvm.zig").targetTriple(arena, target);
     try argv.appendSlice(&[_][]const u8{ "-target", llvm_triple });
 
-    if (target.os.tag == .windows) switch (ext) {
-        .c, .cpp, .m, .mm, .h, .hpp, .hm, .hmm, .cu, .rc, .assembly, .assembly_with_cpp => {
-            const minver: u16 = @truncate(@intFromEnum(target.os.getVersionRange().windows.min) >> 16);
-            try argv.append(
-                try std.fmt.allocPrint(arena, "-D_WIN32_WINNT=0x{x:0>4}", .{minver}),
-            );
-        },
-        else => {},
-    };
-
     switch (ext) {
         .c, .cpp, .m, .mm, .h, .hpp, .hm, .hmm, .cu, .rc => {
             try argv.appendSlice(&[_][]const u8{

src/mingw.zig

@@ -152,6 +152,7 @@ fn add_cc_args(
         "-D_CRTBLD",
         "-D_SYSCRT=1",
         "-DCRTDLL=1",
+        "-D_WIN32_WINNT=0x0f00",
         // According to Martin Storsjö,
         // > the files under mingw-w64-crt are designed to always
         // be built with __MSVCRT_VERSION__=0x700