Only print errno when failure caused by syscall.
Adapt test cases.

--HG--
branch : HEAD

regress/open_cons_extrabytes.test

diff --git a/regress/open_cons_extrabytes.test b/regress/open_cons_extrabytes.test
index e8b1543..8fdf2cc 100644
--- a/regress/open_cons_extrabytes.test
+++ b/regress/open_cons_extrabytes.test
@@ -3,4 +3,4 @@
 file testextrabytes.zip testextrabytes.zip testextrabytes.zip
 args -c testextrabytes.zip
 return 1
-stdout opening `testextrabytes.zip' returned error 21/2
+stdout opening `testextrabytes.zip' returned error 21

regress/open_new_but_exists.test

diff --git a/regress/open_new_but_exists.test b/regress/open_new_but_exists.test
index 612c8c9..9fb0460 100644
--- a/regress/open_new_but_exists.test
+++ b/regress/open_new_but_exists.test
@@ -3,4 +3,4 @@
 args -e test.zip
 return 1
 file test.zip test.zip test.zip
-stdout opening `test.zip' returned error 10/0
+stdout opening `test.zip' returned error 10

regress/open_nonarchive.test

diff --git a/regress/open_nonarchive.test b/regress/open_nonarchive.test
index 3bed520..979a26e 100644
--- a/regress/open_nonarchive.test
+++ b/regress/open_nonarchive.test
@@ -3,4 +3,4 @@
 file Makefile.am Makefile.am Makefile.am
 args Makefile.am
 return 1
-stdout opening `Makefile.am' returned error 19/0
+stdout opening `Makefile.am' returned error 19

regress/tryopen.c

diff --git a/regress/tryopen.c b/regress/tryopen.c
index fcc280f..5997c4a 100644
--- a/regress/tryopen.c
+++ b/regress/tryopen.c
@@ -90,7 +90,9 @@
 	return 0;
     }
 
-    printf("opening `%s' returned error %d/%d\n",
-	   fname, ze, errno);
+    printf("opening `%s' returned error %d", fname, ze);
+    if (zip_error_get_sys_type(ze) == ZIP_ET_SYS)
+	printf("/%d", errno);
+    printf("\n");
     return 1;
 }