[clang] [clang] Support __typeof_unqual__ in all C modes (PR #87392)

[via cfe-commits]

================
@@ -665,28 +665,30 @@ KEYWORD(__kindof                     , KEYOBJC)
 
 // Alternate spelling for various tokens.  There are GCC extensions in all
 // languages, but should not be disabled in strict conformance mode.
-ALIAS("__alignof__"  , __alignof  , KEYALL)
-ALIAS("__asm"        , asm        , KEYALL)
-ALIAS("__asm__"      , asm        , KEYALL)
-ALIAS("__attribute__", __attribute, KEYALL)
-ALIAS("__complex"    , _Complex   , KEYALL)
-ALIAS("__complex__"  , _Complex   , KEYALL)
-ALIAS("__const"      , const      , KEYALL)
-ALIAS("__const__"    , const      , KEYALL)
-ALIAS("__decltype"   , decltype   , KEYCXX)
-ALIAS("__imag__"     , __imag     , KEYALL)
-ALIAS("__inline"     , inline     , KEYALL)
-ALIAS("__inline__"   , inline     , KEYALL)
-ALIAS("__nullptr"    , nullptr    , KEYCXX)
-ALIAS("__real__"     , __real     , KEYALL)
-ALIAS("__restrict"   , restrict   , KEYALL)
-ALIAS("__restrict__" , restrict   , KEYALL)
-ALIAS("__signed"     , signed     , KEYALL)
-ALIAS("__signed__"   , signed     , KEYALL)
-ALIAS("__typeof"     , typeof     , KEYALL)
-ALIAS("__typeof__"   , typeof     , KEYALL)
-ALIAS("__volatile"   , volatile   , KEYALL)
-ALIAS("__volatile__" , volatile   , KEYALL)
+ALIAS("__alignof__"      , __alignof    , KEYALL)
+ALIAS("__asm"            , asm          , KEYALL)
+ALIAS("__asm__"          , asm          , KEYALL)
+ALIAS("__attribute__"    , __attribute  , KEYALL)
+ALIAS("__complex"        , _Complex     , KEYALL)
+ALIAS("__complex__"      , _Complex     , KEYALL)
+ALIAS("__const"          , const        , KEYALL)
+ALIAS("__const__"        , const        , KEYALL)
+ALIAS("__decltype"       , decltype     , KEYCXX)
+ALIAS("__imag__"         , __imag       , KEYALL)
+ALIAS("__inline"         , inline       , KEYALL)
+ALIAS("__inline__"       , inline       , KEYALL)
+ALIAS("__nullptr"        , nullptr      , KEYCXX)
+ALIAS("__real__"         , __real       , KEYALL)
+ALIAS("__restrict"       , restrict     , KEYALL)
+ALIAS("__restrict__"     , restrict     , KEYALL)
+ALIAS("__signed"         , signed       , KEYALL)
+ALIAS("__signed__"       , signed       , KEYALL)
+ALIAS("__typeof"         , typeof       , KEYALL)
+ALIAS("__typeof__"       , typeof       , KEYALL)
+ALIAS("__typeof_unqual"  , typeof_unqual, KEYNOCXX)
+ALIAS("__typeof_unqual__", typeof_unqual, KEYNOCXX)
----------------
h-vetinari wrote:

The C++ rejection should be questioned IMO. To my understanding, once upon a time C++ went with `decltype` to not steal `typeof` from C, waiting for WG14 to standardize it (and once that happened - admittedly decades later -, it was [explicitly](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2930.pdf) made more compatible with C++ during that process). Now that it's finally there, clang could reasonably expose this in all C/C++ modes, also without the leading underscores.

https://github.com/llvm/llvm-project/pull/87392