Remove HAVE_CXX11_CONSTEXPR, always true now

...after 84b36c70 "Drop support for MSVC 2013".

Make this a fatal configuration error for now.  The check should be removed
completely after LO 5.4 branch-off.

Change-Id: I990fd8fcb4ec1327282df4efe21640c938d3cf06
Reviewed-on: https://gerrit.libreoffice.org/34821Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
Tested-by: Stephan Bergmann <sbergman@redhat.com>

config_host/config_global.h.in

@@ -12,7 +12,6 @@ Any change in this header will cause a rebuild of almost everything.
 #ifndef CONFIG_GLOBAL_H
 #define CONFIG_GLOBAL_H
 
-#define HAVE_CXX11_CONSTEXPR 0
 #define HAVE_CXX14_CONSTEXPR 0
 #define HAVE_CXX11_REF_QUALIFIER 0
 #define HAVE_CXX11_UTF16_STRING_LITERAL 0

configure.ac

@@ -6244,8 +6244,8 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 AC_LANG_POP([C++])
 CXXFLAGS=$save_CXXFLAGS
 AC_MSG_RESULT([$cxx11_constexpr])
-if test "$cxx11_constexpr" = yes; then
-    AC_DEFINE([HAVE_CXX11_CONSTEXPR])
+if test "$cxx11_constexpr" = no; then
+    AC_MSG_ERROR([Your $CXX does not support 'constexpr'. This is no longer supported.])
 fi
 
 AC_MSG_CHECKING([whether $CXX supports C++14 constexpr])

include/o3tl/typed_flags_set.hxx

@@ -77,7 +77,7 @@ struct is_typed_flags {
             typename std::underlying_type<E>::type value):
             value_(value)
         {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
             assert(detail::isNonNegative(value));
             assert(
                 static_cast<typename std::underlying_type<E>::type>(~0) == M
@@ -106,7 +106,7 @@ struct is_typed_flags {
 
 template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator ~(E rhs) {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(rhs)));
@@ -129,7 +129,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator ^(
     E lhs, E rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(lhs)));
@@ -146,7 +146,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator ^(
     E lhs, typename o3tl::typed_flags<E>::Wrap rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(lhs)));
@@ -160,7 +160,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator ^(
     typename o3tl::typed_flags<E>::Wrap lhs, E rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(rhs)));
@@ -188,7 +188,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator &(
     E lhs, E rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(lhs)));
@@ -205,7 +205,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator &(
     E lhs, typename o3tl::typed_flags<E>::Wrap rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(lhs)));
@@ -219,7 +219,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator &(
     typename o3tl::typed_flags<E>::Wrap lhs, E rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(rhs)));
@@ -245,7 +245,7 @@ typename o3tl::typed_flags<typename W::Unwrapped::Self>::Wrap operator &(
 
 template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator |(E lhs, E rhs) {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(lhs)));
@@ -262,7 +262,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator |(
     E lhs, typename o3tl::typed_flags<E>::Wrap rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(lhs)));
@@ -276,7 +276,7 @@ template<typename E>
 inline SAL_CONSTEXPR typename o3tl::typed_flags<E>::Wrap operator |(
     typename o3tl::typed_flags<E>::Wrap lhs, E rhs)
 {
-#if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
+#if HAVE_CXX14_CONSTEXPR
     assert(
         o3tl::detail::isNonNegative(
             static_cast<typename std::underlying_type<E>::type>(rhs)));

include/sal/types.h

@@ -422,7 +422,7 @@ namespace css = ::com::sun::star;
 
     @since LibreOffice 5.0
 */
-#if HAVE_CXX11_CONSTEXPR
+#if defined LIBO_INTERNAL_ONLY
 #define SAL_CONSTEXPR constexpr
 #else
 #define SAL_CONSTEXPR

include/vcl/vclptr.hxx

@@ -65,8 +65,7 @@ public:
     typedef typename C< value, void *, void >::t t;
 };
 
-#if HAVE_CXX11_CONSTEXPR \
-    && !(defined _MSC_VER && _MSC_VER <= 1900 && !defined __clang__)
+#if !(defined _MSC_VER && _MSC_VER <= 1900 && !defined __clang__)
 
 template<typename>
 constexpr bool isIncompleteOrDerivedFromVclReferenceBase(...) { return true; }
@@ -93,8 +92,7 @@ namespace detail {
 template <class reference_type>
 class VclPtr
 {
-#if HAVE_CXX11_CONSTEXPR \
-    && !(defined _MSC_VER && _MSC_VER <= 1900 && !defined __clang__)
+#if !(defined _MSC_VER && _MSC_VER <= 1900 && !defined __clang__)
     static_assert(
         vcl::detail::isIncompleteOrDerivedFromVclReferenceBase<reference_type>(
             nullptr),