diff -up testthat/testthat/inst/include/testthat/vendor/catch.h.sigstksz-not-constant testthat/testthat/inst/include/testthat/vendor/catch.h
--- testthat/testthat/inst/include/testthat/vendor/catch.h.sigstksz-not-constant	2021-03-08 13:42:10.853651874 -0500
+++ testthat/testthat/inst/include/testthat/vendor/catch.h	2021-03-08 13:42:36.079767324 -0500
@@ -6492,7 +6492,7 @@ namespace Catch {
         static bool isSet;
         static struct sigaction oldSigActions [sizeof(signalDefs)/sizeof(SignalDefs)];
         static stack_t oldSigStack;
-        static char altStackMem[SIGSTKSZ];
+        static char altStackMem[32768];
 
         static void handleSignal( int sig ) {
             std::string name = "<unknown signal>";
@@ -6512,7 +6512,7 @@ namespace Catch {
             isSet = true;
             stack_t sigStack;
             sigStack.ss_sp = altStackMem;
-            sigStack.ss_size = SIGSTKSZ;
+            sigStack.ss_size = 32768;
             sigStack.ss_flags = 0;
             sigaltstack(&sigStack, &oldSigStack);
             struct sigaction sa = { 0 };
@@ -6543,7 +6543,7 @@ namespace Catch {
     bool FatalConditionHandler::isSet = false;
     struct sigaction FatalConditionHandler::oldSigActions[sizeof(signalDefs)/sizeof(SignalDefs)] = {};
     stack_t FatalConditionHandler::oldSigStack = {};
-    char FatalConditionHandler::altStackMem[SIGSTKSZ] = {};
+    char FatalConditionHandler::altStackMem[32768] = {};
 
 } // namespace Catch