japanese/scim-anthy: Fix build with Clang 6

/usr/local/include/scim-1.0/scim_types.h:38:11: warning: 'STDC_ISO_10646' macro redefined [-Wmacro-redefined]

define STDC_ISO_10646

^

<command line>:6:9: note: previous definition is here
#define STDC_ISO_10646 1

^

scim_anthy_prefs.cpp:98:9: error: cannot initialize a member subobject of type 'void *' with an rvalue of type 'bool'

false,
^~~~~

http://beefy12.nyi.freebsd.org/data/head-amd64-default/p478276_s338342/logs/errors/ja-scim-anthy-1.2.7_5.log

• scim-anthy finds dependencies in LOCALBASE on its own
• STDC_ISO_10646 no longer needs to be specified manually
• Add license while here