[libcxx][AIX][z/OS] Remove headers included via _IBMCPP__

D127650 removed support for non-clang-based XL compilers, but left some
of the headers used only by this compiler and included under the
__IBMCPP__ macro. This change cleans this up by deleting these headers.

Reviewed By: hubert.reinterpretcast, fanbo-meng

Differential Revision: https://reviews.llvm.org/D129491

Author: daltenty

libcxx/include/CMakeLists.txt

@@ -476,10 +476,8 @@ set(files
   __support/android/locale_bionic.h
   __support/fuchsia/xlocale.h
   __support/ibm/gettod_zos.h
-  __support/ibm/limits.h
   __support/ibm/locale_mgmt_zos.h
   __support/ibm/nanosleep.h
-  __support/ibm/support.h
   __support/ibm/xlocale.h
   __support/musl/xlocale.h
   __support/newlib/xlocale.h

libcxx/include/__locale

@@ -33,7 +33,7 @@
 # include <__support/newlib/xlocale.h>
 #elif defined(__OpenBSD__)
 # include <__support/openbsd/xlocale.h>
-#elif (defined(__APPLE__) || defined(__FreeBSD__) || defined(__IBMCPP__))
+#elif (defined(__APPLE__) || defined(__FreeBSD__))
 # include <xlocale.h>
 #elif defined(__Fuchsia__)
 # include <__support/fuchsia/xlocale.h>

libcxx/include/__support/ibm/limits.h

@@ -75,9 +75,6 @@ namespace std {
 #  include <iosfwd>
 #endif
 
-#if defined(__IBMCPP__)
-#  include "__support/ibm/support.h"
-#endif
 #if defined(_LIBCPP_COMPILER_MSVC)
 #  include <intrin.h>
 #endif

libcxx/include/__support/ibm/support.h

@@ -110,10 +110,6 @@ template<> class numeric_limits<cv long double>;
 #include "__support/win32/limits_msvc_win32.h"
 #endif // _LIBCPP_MSVCRT
 
-#if defined(__IBMCPP__)
-#include "__support/ibm/limits.h"
-#endif // __IBMCPP__
-
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif