Revert "Suppress non-conforming GNU paste extension in all standard-conforming modes"

This reverts commit f4537935dcdbf390c863591cf556e76c3abab9c1.
This reverts commit b43c26d036dcbf7a6881f39e4434cf059364022a.

This GNU and MSVC extension turns out to be very popular. Most projects
are not using C++20, so cannot use the new __VA_OPT__ feature to be
standards conformant. The other workaround, using -std=gnu*, enables too
many language extensions and isn't viable.

Until there is a way for users to get the behavior provided by the
`, ## __VA_ARGS__` extension in the -std=c++17 and earlier language
modes, we need to revert this.

1 files changed, 5 insertions, 5 deletions

diff --git a/clang/lib/Lex/TokenLexer.cpp b/clang/lib/Lex/TokenLexer.cpp
index 97cb2cf..da5681a 100644
--- a/clang/lib/Lex/TokenLexer.cpp
+++ b/clang/lib/Lex/TokenLexer.cpp
@@ -148,12 +148,12 @@ bool TokenLexer::MaybeRemoveCommaBeforeVaArgs(
     return false;
 
   // GCC removes the comma in the expansion of " ... , ## __VA_ARGS__ " if
-  // __VA_ARGS__ is empty, but not in strict mode where there are no
-  // named arguments, where it remains.  With GNU extensions, it is removed
-  // regardless of named arguments.
+  // __VA_ARGS__ is empty, but not in strict C99 mode where there are no
+  // named arguments, where it remains.  In all other modes, including C99
+  // with GNU extensions, it is removed regardless of named arguments.
   // Microsoft also appears to support this extension, unofficially.
-  if (!PP.getLangOpts().GNUMode && !PP.getLangOpts().MSVCCompat &&
-      Macro->getNumParams() < 2)
+  if (PP.getLangOpts().C99 && !PP.getLangOpts().GNUMode
+        && Macro->getNumParams() < 2)
     return false;
 
   // Is a comma available to be removed?