Added signal handlers (and placeholder for SEH handlers)

- based on PR 232 (https://github.com/philsquared/Catch/pull/232 - thanks Lukasz Forynski)
- Writes to reporter, so gets all the usual context, but then exits directly (since the stack cannot be resumed) so no summary
- On Windows does nothing, as yet.

include/internal/catch_fatal_condition.hpp

@@ -0,0 +1,78 @@
+/*
+ *  Created by Phil on 21/08/2014
+ *  Copyright 2014 Two Blue Cubes Ltd. All rights reserved.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ *
+ */
+#ifndef TWOBLUECUBES_CATCH_FATAL_CONDITION_H_INCLUDED
+#define TWOBLUECUBES_CATCH_FATAL_CONDITION_H_INCLUDED
+
+
+namespace Catch {
+
+    // Report the error condition then exit the process
+    inline void fatal( std::string const& message, int exitCode ) {
+        IContext& context = Catch::getCurrentContext();
+        IResultCapture* resultCapture = context.getResultCapture();
+        ResultBuilder resultBuilder = resultCapture->makeUnexpectedResultBuilder();
+        resultBuilder.setResultType( ResultWas::FatalErrorCondition );
+        resultBuilder << message;
+        resultBuilder.captureExpression();
+        
+		if( Catch::alwaysTrue() ) // avoids "no return" warnings
+            exit( exitCode );
+    }
+
+} // namespace Catch
+
+#if defined ( CATCH_PLATFORM_WINDOWS ) /////////////////////////////////////////
+
+namespace Catch {
+
+    struct FatalConditionHandler {};
+
+} // namespace Catch
+
+#else // Not Windows - assumed to be POSIX compatible //////////////////////////
+
+#include <signal.h>
+
+namespace Catch {
+
+    struct SignalDefs { int id; const char* name; };
+    extern SignalDefs signalDefs[];
+    SignalDefs signalDefs[] = {
+            { SIGINT,  "SIGINT - Terminal interrupt signal" },
+            { SIGILL,  "SIGILL - Illegal instruction signal" },
+            { SIGFPE,  "SIGFPE - Floating point error signal" },
+            { SIGSEGV, "SIGSEGV - Segmentation violation signal" },
+            { SIGTERM, "SIGTERM - Termination request signal" },
+            { SIGABRT, "SIGABRT - Abort (abnormal termination) signal" }
+        };
+
+    struct FatalConditionHandler {
+
+        static void handleSignal( int sig ) {
+            for( std::size_t i = 0; i < sizeof(signalDefs)/sizeof(SignalDefs); ++i )
+                if( sig == signalDefs[i].id )
+                    fatal( signalDefs[i].name, -sig );
+            fatal( "<unknown signal>", -sig );
+        }
+
+        FatalConditionHandler() {
+            for( std::size_t i = 0; i < sizeof(signalDefs)/sizeof(SignalDefs); ++i )
+                signal( signalDefs[i].id, handleSignal );
+        }
+        ~FatalConditionHandler() {
+            for( std::size_t i = 0; i < sizeof(signalDefs)/sizeof(SignalDefs); ++i )
+                signal( signalDefs[i].id, SIG_DFL );
+        }
+    };
+
+} // namespace Catch
+
+#endif // not Windows
+
+#endif // TWOBLUECUBES_CATCH_FATAL_CONDITION_H_INCLUDED