configure.ac: fix error message on non-MacOS X builds
configure.ac: fix error message on non-MacOS X builds

Change-Id: I33c0b7218054d8d879d72a2a47899b39ae8458ca

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