Make the includes field an array in MSVC build scripts

Previously the 'includes' field was a string.  It's slightly nicer to
manage this when it's defined as an array instead. This allows us to
more easily detect and eliminate duplicates.

Reviewed-by: Álvaro Herrera, Andrew Dunstan, Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/CAApHDvpo6g5csCTjc_0C7DMvgFPomVb0Rh-AcW5afd=Ya=LRuw@mail.gmail.com

src/tools/msvc/MSBuildProject.pm

@@ -313,11 +313,8 @@ sub WriteItemDefinitionGroup
 	my $targetmachine =
 	  $self->{platform} eq 'Win32' ? 'MachineX86' : 'MachineX64';
 
-	my $includes = $self->{includes};
-	unless ($includes eq '' or $includes =~ /;$/)
-	{
-		$includes .= ';';
-	}
+	my $includes = join ';', @{$self->{includes}}, "";
+
 	print $f <<EOF;
   <ItemDefinitionGroup Condition="'\$(Configuration)|\$(Platform)'=='$cfgname|$self->{platform}'">
     <ClCompile>

src/tools/msvc/Mkvcbuild.pm

@@ -937,7 +937,7 @@ sub AddTransformModule
 	# Add PL dependencies
 	$p->AddIncludeDir($pl_src);
 	$p->AddReference($pl_proj);
-	$p->AddIncludeDir($pl_proj->{includes});
+	$p->AddIncludeDir($_) for @{$pl_proj->{includes}};
 	foreach my $pl_lib (@{ $pl_proj->{libraries} })
 	{
 		$p->AddLibrary($pl_lib);
@@ -947,7 +947,7 @@ sub AddTransformModule
 	if ($type_proj)
 	{
 		$p->AddIncludeDir($type_src);
-		$p->AddIncludeDir($type_proj->{includes});
+		$p->AddIncludeDir($_) for @{$type_proj->{includes}};
 		foreach my $type_lib (@{ $type_proj->{libraries} })
 		{
 			$p->AddLibrary($type_lib);

src/tools/msvc/Project.pm

@@ -30,7 +30,7 @@ sub _new
 		references            => [],
 		libraries             => [],
 		suffixlib             => [],
-		includes              => '',
+		includes              => [],
 		prefixincludes        => '',
 		defines               => ';',
 		solution              => $solution,
@@ -151,13 +151,15 @@ sub AddLibrary
 
 sub AddIncludeDir
 {
-	my ($self, $inc) = @_;
+	my ($self, $incstr) = @_;
 
-	if ($self->{includes} ne '')
+	foreach my $inc (split(/;/, $incstr))
 	{
-		$self->{includes} .= ';';
+		if (! grep { $_ eq $inc} @{ $self->{includes} })
+		{
+			push @{ $self->{includes} }, $inc;
+		}
 	}
-	$self->{includes} .= $inc;
 	return;
 }