pkg/55623: cannot install gcc > 4 (w/o forcing) due to incorrect dependency

[bruce.lilly+nbsd%gmail.com@localhost]

>Number:         55623
>Category:       pkg
>Synopsis:       cannot install gcc > 4 (w/o forcing) due to incorrect dependency
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Aug 29 15:45:00 +0000 2020
>Originator:     Bruce Lilly
>Release:        9.0
>Organization:
>Environment:
NetBSD cq60-615dx.blilly.net 9.0 NetBSD 9.0 (GENERIC) #0: Fri Feb 14 00:06:28 UTC 2020  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64 x86_64 Intel 686-class NetBSD
>Description:
Attempts to install gcc5 - gcc10 fail due to alleged dependency on /usr/lib/libstdc++.so.7 (netbsd 9.0 install has /usr/lib/libstdc__.so.9, but not .7).

But the required libstdc++.so.7 is in fact contained in the relevant -libs packages, installed under /usr/pkg/gcc*/* (see under fix for details for gcc5)
>How-To-Repeat:
Fresh install (not upgrade) of NetBSD 9.0
Try to install gcc5 or later via pkgin or pkg_add

>Fix:
Install the relevant matching -libs package (e.g. gcc5-libs; that should work)
Force install of the gcc package, e.g. pkg_add -fUD gcc5
[mnemonic for frustration, uncertainty, and doubt :-/]
Verify operation by building some Sea ploose ploose program with gcc5
Verify that the correct shared object is used with ldd, e.g.:
# ldd /src/grap/grap-1.43/grap
/src/grap/grap-1.43/grap:
        -lstdc++.7 => /usr/pkg/gcc5/x86_64--netbsd/lib/./libstdc++.so.7
        -lm.0 => /usr/lib/libm.so.0
        -lc.12 => /usr/lib/libc.so.12
        -lgcc_s.1 => /usr/lib/libgcc_s.so.1
Lather, rinse, repeat for other gcc versions as desired.