[SHLWAPI][SDK][BOOTDATA] Implement SHGetAppCompatFlags (#8137)

Compatibility is a key that the system
works well.
JIRA issue: CORE-19278
- Add appcompat.c.
- Implement SHGetAppCompatFlags
  function.
- Add Str_SetPtrA prototype to
  <commctrl.h>.
- Add SHACF_... flags to
  <shlwapi_undoc.h>.
- Add comctl32 delay import
  (for Str_SetPtrA).
- Modify boot/bootdata/hivesft.inf
  for registry key
  HRESULTKLM\SOFTWARE\Microsoft\
  Windows\CurrentVersion\
  ShellCompatibility\Applications.

sdk/include/psdk/commctrl.h

@@ -4879,12 +4879,24 @@ typedef struct {
     _In_ LPARAM lParam,
     _In_ UINT options);
 
+  WINCOMMCTRLAPI
+  BOOL
+  WINAPI Str_SetPtrA(
+    _Inout_ LPSTR *ppsz,
+    _In_opt_ LPCSTR psz);
+
   WINCOMMCTRLAPI
   BOOL
   WINAPI Str_SetPtrW(
     _Inout_ LPWSTR *ppsz,
     _In_opt_ LPCWSTR psz);
 
+#ifdef UNICODE
+#define Str_SetPtr Str_SetPtrW
+#else
+#define Str_SetPtr Str_SetPtrA
+#endif
+
 typedef struct _DPASTREAMINFO {
   int iPos;
   void *pvItem;