[glib: 1/2] Revert "Use C++11 decltype where possible"

[Philip Withnall <pwithnall src gnome org>]

commit 1655dc988c5c0650e5d031bbe58394b15cd6fdc1
Author: Philip Withnall <pwithnall endlessos org>
Date:   Wed Oct 21 10:51:14 2020 +0100

    Revert "Use C++11 decltype where possible"
    
    This reverts commit 0d81443ec025b832d3f072a25bdc8e74c13a3919.
    
    It breaks WebKit and GJS, so should be reverted for now. These changes
    may be reintroduced if a solution can be found for the breakage.
    
    See https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1575#note_940048

 glib/gmacros.h         |  4 ----
 glib/tests/cxx.cpp     | 64 --------------------------------------------------
 glib/tests/meson.build |  3 ---
 3 files changed, 71 deletions(-)
---
diff --git a/glib/gmacros.h b/glib/gmacros.h
index 0dd9a41c2..01139b271 100644
--- a/glib/gmacros.h
+++ b/glib/gmacros.h
@@ -234,10 +234,6 @@
 #undef glib_typeof
 #if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) && !defined(__cplusplus)
 #define glib_typeof(t) __typeof__ (t)
-#elif defined(__cplusplus) && __cplusplus >= 201103L
-/* C++11 decltype() is close enough for our usage */
-#include <type_traits>
-#define glib_typeof(t) std::remove_reference<decltype (t)>::type
 #endif
 
 /*
diff --git a/glib/tests/meson.build b/glib/tests/meson.build
index 1c78dbf08..567f5eda4 100644
--- a/glib/tests/meson.build
+++ b/glib/tests/meson.build
@@ -14,9 +14,6 @@ glib_tests = {
   'collate' : {},
   'cond' : {},
   'convert' : {},
-  'cxx' : {
-    'source' : ['cxx.cpp'],
-  },
   'dataset' : {},
   'date' : {},
   'dir' : {},