Rebasing AUDK upon edk2-stable202511

[MikhailKrichanov]

In edk2-stable202511 openssl submodule was updated, what added new external dependency for XCODE5. To fix XCODE5 compilation of SecurityPkg and other packages I had to export CPATH environment variable.
That variable introduced conflicts in OpenCore, which were overcome by this commit.

OpenCorePkg/Library/OcGuardLib/Ubsan.h uses:

#define intptr_t INTN
#define uintptr_t UINTN

but also includes <stddef.h>, which leads to conflicts with sys/_types/_intptr_t.h:

typedef __darwin_intptr_t       intptr_t;

I'm not sure, whether conditional compilation is the best solution.

[mikebeaton]

@MikhailKrichanov - It is worth noting that the OpenSSL code is able to compile and run if __APPLE__ is not defined. E.g. you can manually modify the conditional to # elif defined(___APPLE__) (extra leading underscore) to test and confirm this. It might suit our purposes better to undefine __APPLE__ just for building the OpenSSL derived code?