Fix unportable test(1) operator in configure (#575)
Fix unportable test(1) operator in configure (#575)

'=' is the standard one, only some shells support '=='.
alexhenrie/poedit,vslavik/poedit,alexhenrie/poedit,PKRoma/poedit,alexhenrie/poedit,alexhenrie/poedit,nawawi/poedit,vslavik/poedit,vslavik/poedit,PKRoma/poedit,nawawi/poedit,vslavik/poedit,nawawi/poedit,PKRoma/poedit,vslavik/poedit,PKRoma/poedit,alexhenrie/poedit,PKRoma/poedit,nawawi/poedit,nawawi/poedit