THROW_CALL macro for use with functions that return a negative errno-style error code

P99_THROW_CALL_NEG_ERRNO.patch

diff -uNr p99-2012-12-03/p99/p99_try.h p99/p99/p99_try.h
--- p99-2012-12-03/p99/p99_try.h	2012-12-03 13:40:29.000000000 +0100
+++ p99/p99/p99_try.h	2012-12-04 17:13:46.116666909 +0100
@@ -345,6 +345,20 @@
 #define P00_THROW_CALL_NEG(F, E, ...)                                                                       \
 p00_throw_call_neg(F(__VA_ARGS__), E, p00_unwind_top, P99_STRINGIFY(__LINE__), __func__, #F ", neg return")
 
+p99_inline
+int p00_throw_call_neg_errno(int p00_neg_errno,
+                             errno_t p00_def,
+                             p00_jmp_buf0 * p00_top,
+                             char const* p00_file,
+                             char const* p00_context,
+                             char const* p00_info) {
+  if (P99_UNLIKELY(p00_neg < 0)) p00_jmp_throw(-p00_neg, p00_top, p00_file, p00_context, p00_info);
+  return p00_neg;
+}
+
+#define P00_THROW_CALL_NEG(F, E, ...)                                                                       \
+p00_throw_call_neg_errno(F(__VA_ARGS__), E, p00_unwind_top, P99_STRINGIFY(__LINE__), __func__, #F ", neg return")
+
 /**
  ** @brief Wrap a function call to @a F such that it throws an error
  ** on negative return.
@@ -365,6 +379,7 @@
  ** pointer return value
  **/
 #define P99_THROW_CALL_NEG(F, E, ...) P00_THROW_CALL_NEG(F, E, __VA_ARGS__)
+#define P99_THROW_CALL_NEG_ERRNO(F, E, ...) P00_THROW_CALL_NEG_ERRNO(F, E, __VA_ARGS__)
 
 p99_inline
 void* p00_throw_call_voidp(void* p00_p,