send-email tests: support GIT_TEST_PERL_FATAL_WARNINGS=true

Add support for the "GIT_TEST_PERL_FATAL_WARNINGS=true" test mode to
"send-email". This was added to e.g. git-svn in 5338ed2b26 (perl:
check for perl warnings while running tests, 2020-10-21), but not
"send-email". Let's rectify that.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-send-email.perl b/git-send-email.perl
index 25be2ebd2afb2789afd6373a11dcadd824b5f057..1630e87cd4df7e486fed5681cefcd0abcec8204a 100755 (executable)
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -18,7 +18,7 @@
 
 use 5.008;
 use strict;
-use warnings;
+use warnings $ENV{GIT_PERL_FATAL_WARNINGS} ? qw(FATAL all) : ();
 use POSIX qw/strftime/;
 use Term::ReadLine;
 use Getopt::Long;