Fix prl replacements if libdir is in QMAKE_DEFAULT_LIBDIRS

QMAKE_PRL_LIBS contains absolute paths to libraries, e.g. libqtpcre2.a.
On "make install" the libdir is replaced with the installation target
libdir. If the libdir is in QMAKE_DEFAULT_LIBDIRS (e.g. /usr) then the
replacement was empty. That worked fine for include paths but not for
paths referencing files in that libdir:
/my/build/lib/qtbase/lib/libqtpcre2.a would become /libqtpcre2.a.

Add another replacement that takes care of file paths and inserts
$$[QT_INSTALL_LIBS].

Fixes: QTBUG-75460
Change-Id: I4e84478a50c24d4143ad5695493cad2992735cf2
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Samuli Piippo <samuli.piippo@qt.io>

mkspecs/features/qt_common.prf

@@ -38,6 +38,10 @@ contains(TEMPLATE, .*lib) {
         qt_libdir = $$[QT_INSTALL_LIBS]
     }
     contains(QMAKE_DEFAULT_LIBDIRS, $$qt_libdir) {
+        lib_replace0.match = $$rplbase/lib/
+        lib_replace0.replace = $$qqt_libdir/
+        lib_replace0.CONFIG = path
+        QMAKE_PRL_INSTALL_REPLACE += lib_replace0
         lib_replace.match = "[^ ']*$$rplbase/lib"
         lib_replace.replace =
     } else {