Cygwin: strace: ignore GCC exceptions

Any C++ app that calls 'throw' on 64-bit Cygwin results in an
exception of type STATUS_GCC_THROW (0x20474343) generated by the C++
runtime.  Don't pollute the strace output by printing information
about this and other GCC exceptions.

winsup/utils/strace.cc

@@ -25,6 +25,7 @@ details. */
 #include "../cygwin/include/sys/cygwin.h"
 #include "../cygwin/include/cygwin/version.h"
 #include "../cygwin/cygtls_padsize.h"
+#include "../cygwin/gcc_seh.h"
 #include "path.h"
 #undef cygwin_internal
 #include "loadlib.h"
@@ -790,6 +791,13 @@ proc_child (unsigned mask, FILE *ofile, pid_t pid)
 	    case STATUS_BREAKPOINT:
 	    case 0x406d1388:		/* SetThreadName exception. */
 	      break;
+#ifdef __x86_64__
+	    case STATUS_GCC_THROW:
+	    case STATUS_GCC_UNWIND:
+	    case STATUS_GCC_FORCED:
+	      status = DBG_EXCEPTION_NOT_HANDLED;
+	      break;
+#endif
 	    default:
 	      status = DBG_EXCEPTION_NOT_HANDLED;
 	      if (ev.u.Exception.dwFirstChance)