Allow MSVC to build with Tcl 8.6.

Commit eaba54c20c5 added support for Tcl 8.6 for configure-supported
platforms after verifying that pltcl works without further changes, but
the MSVC tooling wasn't updated accordingly.  Update MSVC to match,
restructuring the code to avoid duplicating the logic for every Tcl
version supported.

Backpatch to all live branches, like eaba54c20c5.  In 9.4 and previous,
change the patch to use backslashes rather than forward, as in the rest
of the file.

Reported by Paresh More, who also tested the patch I provided.
Discussion: https://postgr.es/m/CAAgiCNGVw3ssBtSi3ZNstrz5k00ax=UV+_ZEHUeW_LMSGL2sew@mail.gmail.com

diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index cd18f00a1c76b60fcbea76a5d52cd75797804aff..57569f1f370505e5b0dd5d3cdc418ced268a4d7b 100644 (file)
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -249,20 +249,24 @@ sub mkvcbuild
 
    if ($solution->{options}->{tcl})
    {
+       my $found = 0;
        my $pltcl =
          $solution->AddProject('pltcl', 'dll', 'PLs', 'src\pl\tcl');
        $pltcl->AddIncludeDir($solution->{options}->{tcl} . '\include');
        $pltcl->AddReference($postgres);
-       if (-e $solution->{options}->{tcl} . '\lib\tcl85.lib')
-       {
-           $pltcl->AddLibrary(
-               $solution->{options}->{tcl} . '\lib\tcl85.lib');
-       }
-       else
+
+       for my $tclver (qw(86t 85 84))
        {
-           $pltcl->AddLibrary(
-               $solution->{options}->{tcl} . '\lib\tcl84.lib');
+           my $tcllib = $solution->{options}->{tcl} . "\\lib\\tcl$tclver.lib";
+           if (-e $tcllib)
+           {
+               $pltcl->AddLibrary($tcllib);
+               $found = 1;
+               last;
+           }
        }
+       die "Unable to find $solution->{options}->{tcl}\\lib\\tcl.lib"
+           unless $found;
    }
 
    $libpq = $solution->AddProject('libpq', 'dll', 'interfaces',