Skip this test when building with clang

See comment in test-scm-query-strings.c

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23371 57a11ea4-9604-0410-9ed3-97b8803252fd
Remove dialog-preferences2.c from POTFILES.in

Left over from r23331

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23372 57a11ea4-9604-0410-9ed3-97b8803252fd