test infra - Under -DNO_TAINT_SUPPORT skip tests that use -T or -t

This patch uses a collection of heuristics to skip test files which
would die on a perl compiled with -DNO_TAINT_SUPPORT but without
-DSILENT_NO_TAINT_SUPPORT.

-DNO_TAINT_SUPPORT disables taint support in a "safe" way, such that if
you try to use taint mode with the -t or -T options an exception will be
thrown informing you that the perl you are using does not support taint.
(The related setting -DSILENT_NO_TAINT_SUPPORT disables taint support
but causes the -t and -T options to be silently ignored.)

The error from using -t and -T is thrown very early in the process
startup and there is no way to "gracefully" handle it and convert it
into something else, for instance to skip a test file which contains it.

This patch generally fixes our code to skip these tests.

* Make t/TEST and t/harness check shebang lines and use filename checks
  to filter out tests that use -t or -T. Primarily this is the result of
  checking their shebang line, but some cpan/ files are excluded by
  name, either from a very short list of exclusions, or because their
  file name contains the word "taint". Non-cpan test files were fixed
  individually as noted below.

* test.pl - make run_multiple_progs() skip test cases based on the
  switches that are part of the test definition. This function is
  used in a great deal of our internal tests, so it fixes a lot of
  tests in one go.

* XS-APITest/t/call.t, t/run/switchDX.t, lib/B/Deparse.t - Skip a small
  set of tests in each file.

1 files changed, 6 insertions, 3 deletions

diff --git a/ext/XS-APItest/t/call.t b/ext/XS-APItest/t/call.t
index 390ed8de93..1116f286fb 100644
--- a/ext/XS-APItest/t/call.t
+++ b/ext/XS-APItest/t/call.t
@@ -14,7 +14,7 @@ BEGIN {
     plan(538);
     use_ok('XS::APItest')
 };
-
+use Config;
 #########################
 
 # f(): general test sub to be called by call_sv() etc.
@@ -343,8 +343,11 @@ for my $fn_type (qw(eval_pv eval_sv call_sv)) {
 # DAPM 9-Aug-04. A taint test in eval_sv() could die after setting up
 # a new jump level but before pushing an eval context, leading to
 # stack corruption
+SKIP: {
+    skip("Your perl was built without taint support", 1)
+        unless $Config{taint_support};
 
-fresh_perl_is(<<'EOF', "x=2", { switches => ['-T', '-I../../lib'] }, 'eval_sv() taint');
+    fresh_perl_is(<<'EOF', "x=2", { switches => ['-T', '-I../../lib'] }, 'eval_sv() taint');
 use XS::APItest;
 
 my $x = 0;
@@ -357,4 +360,4 @@ sub f {
 eval { my @a = sort f 2, 1;  $x++};
 print "x=$x\n";
 EOF
-
+}