ape: threadsafe errno

store errno on the private process stack so its always per process
and not just per memory space. errno itself becomes a macro
dereferencing int *_errnoloc; which is initialized from main9.s
pointing to the private stack location.

various fixes in programs that just imported errno variable with
"extern int errno;" instead of including <errno.h>.

1 files changed, 1 insertions, 1 deletions

diff --git a/sys/src/cmd/eqn/main.c b/sys/src/cmd/eqn/main.c
index 879b979e5..a0654d867 100644
--- a/sys/src/cmd/eqn/main.c
+++ b/sys/src/cmd/eqn/main.c
@@ -1,4 +1,5 @@
 #include "e.h"
+#include <errno.h>
 
 #define	MAXLINE	3600	/* maximum input line */
 
@@ -92,7 +93,6 @@ getdata(void)
 {
 	int i, type, ln;
 	char fname[100];
-	extern int errno;
 
 	errno = 0;
 	curfile->lineno = 0;