win32: allow heap cache optimization and memory decommit

osdep/main-fn-win.c

@@ -9,6 +9,18 @@
 #include "osdep/terminal.h"
 #include "osdep/main-fn.h"
 
+#ifndef HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION
+
+#define HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION  1
+enum { HeapOptimizeResources = 3 };
+
+struct HEAP_OPTIMIZE_RESOURCES_INFORMATION {
+    DWORD Version;
+    DWORD Flags;
+};
+
+#endif
+
 static bool is_valid_handle(HANDLE h)
 {
     return h != INVALID_HANDLE_VALUE && h != NULL &&
@@ -30,6 +42,13 @@ static void microsoft_nonsense(void)
     // Enable heap corruption detection
     HeapSetInformation(NULL, HeapEnableTerminationOnCorruption, NULL, 0);
 
+    // Allow heap cache optimization and memory decommit
+    struct HEAP_OPTIMIZE_RESOURCES_INFORMATION heap_info = {
+        .Version = HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION
+    };
+    HeapSetInformation(NULL, HeapOptimizeResources, &heap_info,
+                       sizeof(heap_info));
+
     // Always use safe search paths for DLLs and other files, ie. never use the
     // current directory
     SetDllDirectoryW(L"");