Teach configure about distro-packaged external firebird.
Teach configure about distro-packaged external firebird.

Distros seem to omit fb_config when packaging firebird,
pkg-config can be used instead.

Change-Id: I12e5c5892fcdc5de25835f210ebbb941433f2f44

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core