bug#48907: Debug symbols file name discrepancies

[Maxim Cournoyer]

Hello again,

Building everything without grafts does resolve the file name
discrepancy issue, e.g.:

guix build --no-grafts qtdeclarative | xargs -I{} find -L {} -name 
*libQt5Qml.so.5*
/gnu/store/g1gxfbkyxilnx7s6mjdlj697y5n5wazn-qtdeclarative-5.15.2-debug/lib/debug/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15.2.debug
/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5
/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15
/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15.2

guix build --no-grafts jami-qt | tail -1 | xargs -I{} ldd {}/bin/.jami-qt-real 
| grep qtdeclarative
        libQt5QuickWidgets.so.5 => 
/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5QuickWidgets.so.5
 (0x00007f42c79b2000)
        libQt5Quick.so.5 => 
/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Quick.so.5
 (0x00007f42bfb52000)
        libQt5QmlModels.so.5 => 
/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5QmlModels.so.5
 (0x00007f42bface000)
        libQt5Qml.so.5 => 
/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5
 (0x00007f42bef59000)

And the debug symbols are now discovered and usable by GDB.  So this
issue is indeed caused by grafts.

Maxim