From 00aa84f570dff7005d7bbfe1f4e9811fc0093926 Mon Sep 17 00:00:00 2001
From: David 'Digit' Turner <digit+github@google.com>
Date: Wed, 20 Sep 2023 05:50:37 +0200
Subject: [PATCH] Fix Mingw cross-compilation.

The previous pull request broke compilation with the Mingw toolchain,
which does not provide <atlcore.h>. Moreover, this massive header
was only used to expand a macro that generates a static volatile
variable under the hood (which is not necessary here).

Replace it with with a simpler and more portable code path to fix
the build.

Also, ensure that a broken DiskInterfaceTest, which was only disabled
when using the Microsoft compiler, is also disabled for Mingw
(note that the whole test code is inside a #ifdef _WIN32 .. #endif
block).

After this patch, a `ninja_test.exe` generated on Linux with the
Mingw toolchain runs and succeeds properly on a Windows machine.
---
 src/disk_interface.cc      | 20 +++++++++++++-------
 src/disk_interface_test.cc |  2 +-
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/disk_interface.cc b/src/disk_interface.cc
index ed064e1555..0f27e9da44 100644
--- a/src/disk_interface.cc
+++ b/src/disk_interface.cc
@@ -23,10 +23,10 @@
 #include <sys/types.h>
 
 #ifdef _WIN32
-#include <sstream>
-#include <windows.h>
 #include <direct.h>  // _mkdir
-#include <atlcore.h>
+#include <windows.h>
+
+#include <sstream>
 #else
 #include <unistd.h>
 #endif
@@ -162,10 +162,16 @@ RealDiskInterface::RealDiskInterface()
 #ifdef _WIN32
 : use_cache_(false), long_paths_enabled_(false) {
   setlocale(LC_ALL, "");
-  IFDYNAMICGETCACHEDFUNCTIONTYPEDEF(L"ntdll", BOOLEAN(WINAPI*)(),
-    "RtlAreLongPathsEnabled",
-    RtlAreLongPathsEnabled) {
-    long_paths_enabled_ = RtlAreLongPathsEnabled();
+
+  // Probe ntdll.dll for RtlAreLongPathsEnabled, and call it if it exists.
+  HINSTANCE ntdll_lib = ::GetModuleHandleW(L"ntdll");
+  if (ntdll_lib) {
+    typedef BOOLEAN(WINAPI FunctionType)();
+    auto* func_ptr = reinterpret_cast<FunctionType*>(
+        ::GetProcAddress(ntdll_lib, "RtlAreLongPathsEnabled"));
+    if (func_ptr) {
+      long_paths_enabled_ = (*func_ptr)();
+    }
   }
 }
 #else
diff --git a/src/disk_interface_test.cc b/src/disk_interface_test.cc
index e8d869c871..3164a1bae4 100644
--- a/src/disk_interface_test.cc
+++ b/src/disk_interface_test.cc
@@ -171,7 +171,7 @@ TEST_F(DiskInterfaceTest, StatCache) {
   EXPECT_GT(disk_.Stat("subdir/subsubdir", &err), 1);
   EXPECT_EQ("", err);
 
-#ifndef _MSC_VER // TODO: Investigate why. Also see https://github.com/ninja-build/ninja/pull/1423
+#ifndef _WIN32  // TODO: Investigate why. Also see https://github.com/ninja-build/ninja/pull/1423
   EXPECT_EQ(disk_.Stat("subdir", &err),
             disk_.Stat("subdir/.", &err));
   EXPECT_EQ("", err);