Make tap tests store postmaster logs and handle vpaths correctly

Given this it is possible that the buildfarm animals running these tests
will be able to capture adequate logging to allow diagnosis of failures.

src/Makefile.global.in

@@ -338,7 +338,7 @@ cd $(srcdir) && TESTDIR='$(CURDIR)' PATH="$(bindir):$$PATH" PGPORT='6$(DEF_PGPOR
 endef
 
 define prove_check
-rm -rf $(srcdir)/tmp_check/log
+rm -rf $(CURDIR)/tmp_check/log
 cd $(srcdir) && TESTDIR='$(CURDIR)' $(with_temp_install) PGPORT='6$(DEF_PGPORT)' top_builddir='$(CURDIR)/$(top_builddir)' $(PROVE) $(PG_PROVE_FLAGS) $(PROVE_FLAGS) t/*.pl
 endef
 

src/bin/pg_rewind/RewindTest.pm

@@ -72,9 +72,6 @@ our $test_standby_datadir = "$testroot/data_standby";
 
 mkdir $testroot;
 
-# Log files are created here
-mkdir "regress_log";
-
 # Define non-conflicting ports for both nodes.
 my $port_master  = $ENV{PGPORT};
 my $port_standby = $port_master + 1;
@@ -202,6 +199,7 @@ local replication all trust
 
 	system_or_bail('pg_ctl' , '-w',
 				   '-D' , $test_master_datadir,
+				   '-l',  "$log_path/master.log",
 				   "-o", "-k $tempdir_short --listen-addresses='' -p $port_master",
 				   'start');
 
@@ -228,6 +226,7 @@ recovery_target_timeline='latest'
 
 	# Start standby
 	system_or_bail('pg_ctl', '-w', '-D', $test_standby_datadir,
+				   '-l', "$log_path/standby.log",
 				   '-o', "-k $tempdir_short --listen-addresses='' -p $port_standby",
 				   'start');
 
@@ -323,6 +322,7 @@ recovery_target_timeline='latest'
 
 	# Restart the master to check that rewind went correctly
 	system_or_bail('pg_ctl', '-w', '-D', $test_master_datadir,
+				   '-l', "$log_path/master.log",
 				   '-o', "-k $tempdir_short --listen-addresses='' -p $port_master",
 				   'start');
 

src/test/perl/TestLib.pm

@@ -23,6 +23,9 @@ our @EXPORT = qw(
   program_options_handling_ok
   command_like
   issues_sql_like
+
+  $tmp_check
+  $log_path
 );
 
 use Cwd;
@@ -37,8 +40,10 @@ use Test::More;
 
 # Open log file. For each test, the log file name uses the name of the
 # file launching this module, without the .pl suffix.
-my $log_path = 'tmp_check/log';
-mkdir 'tmp_check';
+our ($tmp_check, $log_path);
+$tmp_check = $ENV{TESTDIR} ? "$ENV{TESTDIR}/tmp_check" : "tmp_check";
+$log_path = "$tmp_check/log";
+mkdir $tmp_check;
 mkdir $log_path;
 my $test_logfile = basename($0);
 $test_logfile =~ s/\.[^.]+$//;
@@ -132,19 +137,19 @@ sub start_test_server
 	print("### Starting test server in $tempdir\n");
 	standard_initdb "$tempdir/pgdata";
 	$ret = system_log('pg_ctl', '-D', "$tempdir/pgdata", '-w', '-l',
-	  "$tempdir/logfile", '-o',
+	  "$log_path/postmaster.log", '-o',
 "--fsync=off -k \"$tempdir_short\" --listen-addresses='' --log-statement=all",
 					'start');
 	if ($ret != 0)
 	{
 		print "# pg_ctl failed; logfile:\n";
-		system('cat', "$tempdir/logfile");
+		system('cat', "$log_path/postmaster.log");
 		BAIL_OUT("pg_ctl failed");
 	}
 
 	$ENV{PGHOST}         = $tempdir_short;
 	$test_server_datadir = "$tempdir/pgdata";
-	$test_server_logfile = "$tempdir/logfile";
+	$test_server_logfile = "$log_path/postmaster.log";
 }
 
 sub restart_test_server