graphviz-gui @2.40.1_0 build fails on Mojave

[ShadSterling (Shad Sterling)]

I'm not sure if this is related to #57137, #57830, and/or #57170

Just upgraded to Mojave, attempted to reinstall all ports, and graphviz-gui was the only failure. It looks like the culprit is a missing /Users/macports/Library/Caches/com.apple.ibtool/Cache.db:

:info:build CompileXIB /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_graphviz/graphviz-gui/work/graphviz-2.40.1/macosx/English.lproj/Attributes.xib (in target: application)
:info:build     cd /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_graphviz/graphviz-gui/work/graphviz-2.40.1/macosx
:info:build     export XCODE_DEVELOPER_USR_PATH=/Applications/Xcode.app/Contents/Developer/usr/bin/..
:info:build     /Applications/Xcode.app/Contents/Developer/usr/bin/ibtool --errors --warnings --notices --module Graphviz --output-partial-info-plist /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_graphviz/graphviz-gui/work/graphviz-2.40.1/macosx/build/graphviz.build/Release/application.build/English.lproj/Attributes-PartialInfo.plist --auto-activate-custom-fonts --target-device mac --minimum-deployment-target 10.14 --output-format human-readable-text --compile /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_graphviz/graphviz-gui/work/graphviz-2.40.1/macosx/build/Release/Graphviz.app/Contents/Resources/English.lproj/Attributes.nib /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_graphviz/graphviz-gui/work/graphviz-2.40.1/macosx/English.lproj/Attributes.xib
:info:build 2019-02-24 17:03:40.258 ibtoold[11576:3685999] NetworkStorageDB:_openDBReadConnections: failed to open read connection to DB @ /Users/macports/Library/Caches/com.apple.ibtool/Cache.db.  Error=14. Cause=unable to open database file
:info:build 2019-02-24 17:03:40.258 ibtoold[11576:3685999] CacheRead: unable to open cache files in /Users/macports/Library/Caches/com.apple.ibtool
:info:build 2019-02-24 17:03:40.259 ibtoold[11576:3685999] Failed to obtain sandbox extension for path=/Users/macports/Library/Caches/com.apple.ibtool. Errno:2
:info:build 2019-02-24 17:03:40.259 ibtoold[11576:3685999] NetworkStorageDB:_openDBReadConnections: failed to open read connection to DB @ /Users/macports/Library/Caches/com.apple.ibtool/Cache.db.  Error=14. Cause=unable to open database file
:info:build 2019-02-24 17:03:40.259 ibtoold[11576:3685999] CacheRead: unable to open cache files in /Users/macports/Library/Caches/com.apple.ibtool
:info:build 2019-02-24 17:03:40.259 ibtoold[11576:3685999] Failed to obtain sandbox extension for path=/Users/macports/Library/Caches/com.apple.ibtool. Errno:2
:info:build ** BUILD FAILED **

[ryandesign (Ryan Carsten Schmidt)]

I assume this is #57137. Somebody with Mojave should attempt to fix that.