Don't enable POSIX signals under QNX
Fixes #889
diff --git a/include/internal/catch_compiler_capabilities.h b/include/internal/catch_compiler_capabilities.h
index 325ae02..ac6f259 100644
--- a/include/internal/catch_compiler_capabilities.h
+++ b/include/internal/catch_compiler_capabilities.h
@@ -80,13 +80,20 @@
////////////////////////////////////////////////////////////////////////////////
-// Cygwin
-#ifdef __CYGWIN__
+// We know some environments not to support full POSIX signals
+#if defined(__CYGWIN__) || defined(__QNX__)
# if !defined(CATCH_CONFIG_POSIX_SIGNALS)
# define CATCH_INTERNAL_CONFIG_NO_POSIX_SIGNALS
# endif
+#endif
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Cygwin
+#ifdef __CYGWIN__
+
// Required for some versions of Cygwin to declare gettimeofday
// see: http://stackoverflow.com/questions/36901803/gettimeofday-not-declared-in-this-scope-cygwin
# define _BSD_SOURCE