make h_errno thread-local

the framework to do this always existed but it was deemed unnecessary
because the only [ex-]standard functions using h_errno were not
thread-safe anyway. however, some of the nonstandard res_* functions
are also supposed to set h_errno to indicate the cause of error, and
were unable to do so because it was not thread-safe. this change is a
prerequisite for fixing them.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 5742dfc5..5749a336 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -43,6 +43,7 @@ struct pthread {
 		long off;
 		volatile void *volatile pending;
 	} robust_list;
+	int h_errno_val;
 	volatile int timer_id;
 	locale_t locale;
 	volatile int killlock[1];