[MacPorts] #58441: "port upgrade libgcc8" pulls libgcc9 instead (and fails, of course). Also affects gcc8 port

[MacPorts]

#58441: "port upgrade libgcc8" pulls libgcc9 instead (and fails, of course). Also
affects gcc8 port
------------------------+---------------------
 Reporter:  mouse07410  |      Owner:  (none)
     Type:  defect      |     Status:  new
 Priority:  Normal      |  Milestone:
Component:  ports       |    Version:
 Keywords:              |       Port:  libgcc8
------------------------+---------------------
 MacOS Mojave 10.14.4, Xcode-10.2.1.

 {{{libgcc8}}} port is screwed up - it mistakenly thinks that its upgrade
 it not 8.3.0_4, but {{{libgcc9}}} (which I don't care to install,
 regardless).

 {{{
 $ port outdated
 The following installed ports are outdated:
 gcc8                           8.3.0_0 < 8.3.0_4
 libgcc                         1.0_0 < 2.0_0
 libgcc8                        8.3.0_0 < 8.3.0_3
 $ sudo port upgrade libgcc8
 --->  Computing dependencies for libgcc9
 --->  Fetching archive for libgcc9
 --->  Attempting to fetch libgcc9-9.1.0_0.darwin_18.x86_64.tbz2 from
 https://packages.macports.org/libgcc9
 --->  Attempting to fetch libgcc9-9.1.0_0.darwin_18.x86_64.tbz2 from
 http://ywg.ca.packages.macports.org/mirror/macports/packages/libgcc9
 --->  Attempting to fetch libgcc9-9.1.0_0.darwin_18.x86_64.tbz2 from
 http://aus.us.packages.macports.org/macports/packages/libgcc9
 --->  Fetching distfiles for libgcc9
 --->  Attempting to fetch gcc-9.1.0.tar.xz from
 https://distfiles.macports.org/gcc9
 --->  Verifying checksums for libgcc9
 --->  Extracting libgcc9
 --->  Configuring libgcc9
 --->  Building libgcc9
 Error: Failed to build libgcc9: command execution failed
 Error: See
 /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_lang_gcc9/libgcc9/main.log
 for details.
 Error: Problem while installing libgcc9
 Error: Follow https://guide.macports.org/#project.tickets to report a bug.
 $
 }}}

 This probably explains why - somebody put {{{libgcc9}}} as a runtime
 dependency for {{{libgcc8}}}. As {{{gcc8}}} depends on {{{libgcc8}}}, it
 cannot be updated either.

 Complete log is attached.

-- 
Ticket URL: <https://trac.macports.org/ticket/58441>
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