[glibc] support: Set errno before testing it.

[Carlos O'Donell <carlos@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=183083c35972611e7786c7ee0c96d7da571631ed

commit 183083c35972611e7786c7ee0c96d7da571631ed
Author: Carlos O'Donell <carlos@redhat.com>
Date:   Wed Apr 29 16:31:29 2020 -0400

    support: Set errno before testing it.
    
    In test-conainer we should set errno to 0 before calling strtol,
    and check after with TEST_COMPARE.
    
    In tst-support_capture_subprocess we should set errno to 0 before
    checking it after the call to strtol.
    
    Tested on x86_64.
    
    Reviewed-by: DJ Delorie <dj@redhat.com>

Diff:
---
 support/test-container.c                 | 2 ++
 support/tst-support_capture_subprocess.c | 4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/support/test-container.c b/support/test-container.c
index 08d5195b7e..afc23db148 100644
--- a/support/test-container.c
+++ b/support/test-container.c
@@ -940,7 +940,9 @@ main (int argc, char **argv)
 	    else if (nt == 3 && strcmp (the_words[0], "chmod") == 0)
 	      {
 		long int m;
+		errno = 0;
 		m = strtol (the_words[1], NULL, 0);
+		TEST_COMPARE (errno, 0);
 		if (chmod (the_words[2], m) < 0)
 		    FAIL_EXIT1 ("chmod %s: %s\n",
 				the_words[2], strerror (errno));
diff --git a/support/tst-support_capture_subprocess.c b/support/tst-support_capture_subprocess.c
index 67bbc1e8ae..6094dba49e 100644
--- a/support/tst-support_capture_subprocess.c
+++ b/support/tst-support_capture_subprocess.c
@@ -133,7 +133,9 @@ static int
 parse_int (const char *str)
 {
   char *endptr;
-  long int ret = strtol (str, &endptr, 10);
+  long int ret;
+  errno = 0;
+  ret = strtol (str, &endptr, 10);
   TEST_COMPARE (errno, 0);
   TEST_VERIFY (ret >= 0 && ret <= INT_MAX);
   return ret;