[MacPorts] #56519: libcxx database corrupted, universal broken, weird circular dependency

[MacPorts]

#56519: libcxx database corrupted, universal broken, weird circular dependency
---------------------------------------------+--------------------
 Reporter:  gaming-hacker                    |      Owner:  (none)
     Type:  defect                           |     Status:  new
 Priority:  Normal                           |  Milestone:
Component:  ports                            |    Version:  2.4.3
 Keywords:  libxml2, universal, ghostscript  |       Port:  libcxx
---------------------------------------------+--------------------
 All,

 This port is really hosed, so far this update breaks any builds that uses
 are not built as universal.  I have to wish to support anything i386
 whatsoever. my default is -universal in the macports conf file.

 So I needed to update ghostscript.


 {{{
 UPgrading Port
 --->  Computing dependencies for libcxx
 Error: Cannot install libcxx for the archs 'i386 x86_64' because
 Error: its dependency libxml2 only supports the arch 'x86_64'.
 }}}

 displaying ino on libcxx reveals

 {{{
 Full Name: libcxx @6.0.0+universal
 libcxx @6.0.0_1 (lang)

 The following ports are dependent on libcxx:
   clang-6.0
   cmake
   ld64-latest
     ld64
       gcc8
       libgcc-devel
         libgcc6
         py27-numpy
   llvm-6.0
     cctools
 clang-6.0 depends on libcxx
 cmake depends on libcxx
 ld64-latest depends on libcxx
 llvm-6.0 depends on libcxx
 The following ports are currently installed:
   libcxx @5.0.1_2+universal (active)
 }}}

 the database display the new version but the old version is active.  how
 this is possible, i have no idea.

 i forced an upgrade to libxml2 by creating a revision 1 and resulting
 error is

 {{{
 UPgrading Port
 --->  Computing dependencies for libcxx
 Error: Cannot install libcxx for the archs 'i386 x86_64' because
 Error: its dependency libxml2 only supports the arch 'x86_64'.
 Error: Follow https://guide.macports.org/#project.tickets to report a bug.
 [14:15][226]~/local/macports-ports
 }}}

 now i have to fix a lot of dependencies, zlib, xz, libffi, libedit, etc

 There needs to be a fix so that if the default compiler already relies on
 libcxx, not to use that compiler; in my case clang6.0 and don't require
 universal.

-- 
Ticket URL: <https://trac.macports.org/ticket/56519>
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