Merge branch 'sandbox' into kmiya
Merge branch 'feature-load-ppm' into kmiya
Merge branch 'fix-for-cygwin-environment' into configure-gd-integration
Merge branch 'configure-support-less-featured-gd' into configure-gd-integration
Merge branch 'configure-gd-integration' into gd-integration
Rebuild
Support some environments lack getopt_long
Add a config.h definition which represents getopt_long avilability
Merge branch 'fix-for-lacking-getopt_long' into develop
Merge branch 'gd-integration' into develop

Conflicts:
	configure
Merge branch 'kmiya' into develop
Merge branch 'arakiken' into develop
Merge branch 'feature-wic-integration' of github.com:saitoha/libsixel into develop
Minor fix
Update gitigore
Merge branch 'develop' into feature-wic-integration
+