diff --git a/third_party/include/doctest/doctest.h b/third_party/include/doctest/doctest.h
index 94446982..13ccf272 100644
--- a/third_party/include/doctest/doctest.h
+++ b/third_party/include/doctest/doctest.h
@@ -3940,7 +3940,9 @@ namespace {
 #if !defined(DOCTEST_CONFIG_POSIX_SIGNALS) && !defined(DOCTEST_CONFIG_WINDOWS_SEH)
     struct FatalConditionHandler
     {
-        void reset() {}
+        static void reset() {}
+        static void allocateAltStackMem() {}
+        static void freeAltStackMem() {}
     };
 #else // DOCTEST_CONFIG_POSIX_SIGNALS || DOCTEST_CONFIG_WINDOWS_SEH
 
@@ -3977,6 +3979,9 @@ namespace {
             return EXCEPTION_CONTINUE_SEARCH;
         }
 
+        static void allocateAltStackMem() {}
+        static void freeAltStackMem() {}
+
         FatalConditionHandler() {
             isSet = true;
             // 32k seems enough for doctest to handle stack overflow,
@@ -4029,7 +4034,8 @@ namespace {
         static bool             isSet;
         static struct sigaction oldSigActions[DOCTEST_COUNTOF(signalDefs)];
         static stack_t          oldSigStack;
-        static char             altStackMem[4 * SIGSTKSZ];
+        static size_t           altStackSize;
+        static char*            altStackMem;
 
         static void handleSignal(int sig) {
             const char* name = "<unknown signal>";
@@ -4045,11 +4051,19 @@ namespace {
             raise(sig);
         }
 
+        static void allocateAltStackMem() {
+            altStackMem = new char[altStackSize];
+        }
+
+        static void freeAltStackMem() {
+            delete[] altStackMem;
+        }
+
         FatalConditionHandler() {
             isSet = true;
             stack_t sigStack;
             sigStack.ss_sp    = altStackMem;
-            sigStack.ss_size  = sizeof(altStackMem);
+            sigStack.ss_size  = altStackSize;
             sigStack.ss_flags = 0;
             sigaltstack(&sigStack, &oldSigStack);
             struct sigaction sa = {};
@@ -4074,10 +4088,11 @@ namespace {
         }
     };
 
-    bool             FatalConditionHandler::isSet                                      = false;
+    bool             FatalConditionHandler::isSet = false;
     struct sigaction FatalConditionHandler::oldSigActions[DOCTEST_COUNTOF(signalDefs)] = {};
-    stack_t          FatalConditionHandler::oldSigStack                                = {};
-    char             FatalConditionHandler::altStackMem[]                              = {};
+    stack_t          FatalConditionHandler::oldSigStack = {};
+    size_t           FatalConditionHandler::altStackSize = 4 * SIGSTKSZ;
+    char*            FatalConditionHandler::altStackMem = nullptr;
 
 #endif // DOCTEST_PLATFORM_WINDOWS
 #endif // DOCTEST_CONFIG_POSIX_SIGNALS || DOCTEST_CONFIG_WINDOWS_SEH
@@ -5936,7 +5951,11 @@ int Context::run() {
         p->cout = &fstr;
     }
 
+    FatalConditionHandler::allocateAltStackMem();
+
     auto cleanup_and_return = [&]() {
+        FatalConditionHandler::freeAltStackMem();
+
         if(fstr.is_open())
             fstr.close();