Macro redefinition when compiling on windows with clang

[robojan]

Describe the bug
When building catch 2 on windows with clang both the Microsoft visual studio and clang compilers are detected in catch_compiler_capabilities.hpp which results in the following macros being redefined:

• CATCH_INTERNAL_START_WARNINGS_SUPPRESSION
• CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION

The following warnings are generated:

E:/git/robojan/fatpp/build/_deps/catch2-src/src/catch2/..\catch2/internal/catch_compiler_capabilities.hpp:157:11: warning: 'CATCH_INTERNAL_START_WARNINGS_SUPPRESSION' macro redefined [-Wmacro-redefined]
#  define CATCH_INTERNAL_START_WARNINGS_SUPPRESSION __pragma( warning(push) )
          ^
E:/git/robojan/fatpp/build/_deps/catch2-src/src/catch2/..\catch2/internal/catch_compiler_capabilities.hpp:62:13: note: previous definition is here
#    define CATCH_INTERNAL_START_WARNINGS_SUPPRESSION _Pragma( "clang diagnostic push" )
            ^
E:/git/robojan/fatpp/build/_deps/catch2-src/src/catch2/..\catch2/internal/catch_compiler_capabilities.hpp:158:11: warning: 'CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION' macro redefined [-Wmacro-redefined]
#  define CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION  __pragma( warning(pop) )
          ^
E:/git/robojan/fatpp/build/_deps/catch2-src/src/catch2/..\catch2/internal/catch_compiler_capabilities.hpp:63:13: note: previous definition is here
#    define CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION  _Pragma( "clang diagnostic pop" )

Expected behavior
I would expect that no warnings are generated, and the correct compiler was detected.

Reproduction steps
Compile a file which includes catch2/catch_test_macros.hpp with clang 13 on windows

Platform information:

• OS: Windows NT x86_64-pc-windows-msvc
• Compiler+version: Clang 13.0.0
• Catch version: v3.0.0-preview3

Additional context
It may be possible to extend the check for MSVC to
#if defined(_MSC_VER) && !defined(__clang__)
from
#if defined(_MSC_VER)

But it seems that clang masquerading is already handled in the MSVC case. So there may be some implications of this change that i don't see.

[horenmar]

Turns out this is already fixed in devel, by only enabling the clang-specific pragmas if _MSC_VER is not also enabled (in which case we assume that Clang handles __pragmas and let it handle the MSVC macros).