pkg/49904: pkg_select crashes on startup on Mac OS 10.10

[bsiegert%NetBSD.org@localhost]

>Number:         49904
>Category:       pkg
>Synopsis:       pkg_select crashes on startup on Mac OS 10.10
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu May 14 09:00:00 +0000 2015
>Originator:     Benny Siegert
>Release:        pkgsrc-HEAD as of May 2015 (ABI=64)
>Organization:
The NetBSD Foundation
>Environment:
Darwin lem.local 14.3.0 Darwin Kernel Version 14.3.0: Mon Mar 23 11:59:05 PDT 2015; root:xnu-2782.20.48~5/RELEASE_X86_64 x86_64

>Description:
When built on Mac OS 10.10.x 64-bit, pkg_select crashes immediately upon startup. This is what the screen shows:

│ please wait while loading package database...pkg_select(7489,0x7fff74445300) malloc: *** error for object 0x7f9d28700640: incorrect checksum for freed object - object was probably modified after being freed.───────────────────────────────────┘
*** set a breakpoint in malloc_error_break to debug
Abort

Sounds like a use after free.
>How-To-Repeat:
Build pkg_select:

[lem:pkgsrc/pkgtools/pkg_select] bsiegert% bmake describe
pkg_select-20090308nb3|/usr/pkgsrc/pkgtools/pkg_select|/usr/pkg|Curses based pkgsrc system browser / manager|/usr/pkgsrc/pkgtools/pkg_select/DESCR|imil%gcu.info@localhost|pkgtools|||any|any

Run it.

Note that this does not occur on every startup. If you try a couple of times, eventually it will run.
>Fix: