Fix warning: no previous prototype for foo [-Wmissing-prototypes]
Fix warning: no previous prototype for foo [-Wmissing-prototypes]

Related to #322

BueVest/liblouis,hammera/liblouis,BueVest/liblouis,BueVest/liblouis,hammera/liblouis,liblouis/liblouis,hammera/liblouis,liblouis/liblouis,liblouis/liblouis,BueVest/liblouis,BueVest/liblouis,liblouis/liblouis,liblouis/liblouis,BueVest/liblouis,liblouis/liblouis,hammera/liblouis,hammera/liblouis,hammera/liblouis