SIGSTKSZ no longer a compile time constant, which fails the compilation of `test_manager-safe_array_tb`

[astrojhgu]

See
https://lists.gnu.org/archive/html/bug-m4/2021-03/msg00013.html
doctest/doctest#473

As a temp work around, I define SIGSTKSZ to be 8192

diff --git a/src/catch.hpp b/src/catch.hpp
index 7c351e9..a5ed5e3 100644
--- a/src/catch.hpp
+++ b/src/catch.hpp
@@ -6478,6 +6478,7 @@ namespace Catch {
 #  else // CATCH_CONFIG_POSIX_SIGNALS is defined
 
 #include <signal.h>
+#define SIGSTKSZ 8192
 
 namespace Catch {
 

, which I think is not a good enough method.

[StefanBruens]

The better option is to replace the bundled catch.hpp with a current one (though, use Catch2 < 3.0, as 3.0 is no longer header-only).