LCC: Add dedicated support for MCST LCC compiler

Divert LCC compiler as a new one, instead of treating it as GNU.

Since old times, Elbrus C/C++/Fortran Compiler (LCC) by MCST has been
passing checks for GNU compilers, so it has been identified as GNU.
Now, with intent of seriously upstreaming its support, it has been
added as a separate LCC compiler, and its version displays not a
supported GCC version, but LCC version itself (e.g. LCC 1.25.19 instead
of GNU 7.3.0).

This commit adds its support for detection, and also converts basically
every check like 'is this compiler GNU?' to 'is this compiler GNU or
LCC?'. The only places where this check is untouched, is where it
regards other platforms where LCC is unavailable (primarily non-Linux),
and where it REALLY differs from GNU compiler.

Note: this transition may break software that are already ported to
Elbrus, but hardly relies that LCC will be detected as GNU; still such
software is not known.

1 files changed, 5 insertions, 2 deletions

diff --git a/Tests/CompileFeatures/cxx_generalized_initializers.cpp b/Tests/CompileFeatures/cxx_generalized_initializers.cpp
index bfe0d41..c4f47fe 100644
--- a/Tests/CompileFeatures/cxx_generalized_initializers.cpp
+++ b/Tests/CompileFeatures/cxx_generalized_initializers.cpp
@@ -11,8 +11,11 @@ class initializer_list
   const _E* __begin_;
   size_t __size_;
 
-#ifdef __INTEL_COMPILER
-  // The Intel compiler internally asserts the constructor overloads, so
+#if defined(__INTEL_COMPILER) ||                                              \
+  (defined(__LCC__) &&                                                        \
+   (defined(__GNUC__) || defined(__GNUG__) || defined(__MCST__)))
+  // Compilers based on EDG, such as Intel compiler and MCST LCC,
+  // internally assert the constructor overloads, so
   // reproduce the constructor used in its <initializer_list> header.
   initializer_list(const _E*, size_t) {}
 #else