unictype: Add support for Arabic shaping properties. * lib/unictype.in.h (UC_JOINING_TYPE_*): New enumeration values. (uc_joining_type_name, uc_joining_type_byname, uc_joining_type): New declarations. (UC_JOINING_GROUP_*): New enumeration values. (uc_joining_group_name, uc_joining_group_byname, uc_joining_group): New declarations. * lib/gen-uni-tables.c (UC_JOINING_TYPE_*): New enumeration values. (unicode_joining_type): New variable. (UC_JOINING_GROUP_*): New enumeration values. (unicode_joining_group): New variable. (fill_arabicshaping, joining_type_as_c_identifier, output_joining_type_test, output_joining_type, joining_group_as_c_identifier, output_joining_group_test, output_joining_group): New functions. (main); Add an argument denoting the ArabicShaping.txt file. Invoke fill_arabicshaping and output_joining_type_test, output_joining_type, output_joining_group_test, output_joining_group. Reported by Simon Josefsson.