New review comment by ypsvlq on void-packages repository

https://github.com/void-linux/void-packages/pull/37480#discussion_r967860267

Comment:
Not specifying it there causes 
```
=== configuring in src/resid (/builddir/vice-3.6.1/src/resid)
configure: running /bin/sh ./configure '--prefix=/usr' --disable-option-checking  '--sysconfdir=/etc' '--sbindir=/usr/bin' '--bindir=/usr/bin' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--localstatedir=/var' '--host=x86_64-unknown-linux-gnu' '--build=x86_64-unknown-linux-gnu' '--libdir=NONE/lib64' '--disable-sdlui2' '--without-sdlsound' '--enable-native-gtk3ui' '--enable-desktop-files' '--with-pulse' '--enable-external-ffmpeg' '--enable-cpuhistory' '--enable-x64' '--disable-pdf-docs' 'build_alias=x86_64-unknown-linux-gnu' 'host_alias=x86_64-unknown-linux-gnu' 'CC=cc' 'CFLAGS=-fstack-clash-protection -D_FORTIFY_SOURCE=2 -mtune=generic -O2 -pipe    -fdebug-prefix-map=/builddir/vice-3.6.1=.' 'LDFLAGS=-Wl,-z,relro -Wl,-z,now -Wl,--as-needed    ' 'CPPFLAGS=
 ' 'CPP=cpp' 'CXX=g++' 'CXXFLAGS=-fstack-clash-protection -D_FORTIFY_SOURCE=2 -mtune=generic -O2 -pipe    -fdebug-prefix-map=/builddir/vice-3.6.1=.' 'PKG_CONFIG=pkg-config' '--disable-option-checking' '--srcdir=.' --cache-file=
configure: error: expected an absolute directory name for --libdir: NONE/lib64
configure: error: ./configure failed for src/resid
=> ERROR: vice-3.6.1_1: do_configure: '${configure_script} ${configure_args}' exited with 1
```
(presumably it's lack of exec_prefix somewhere)