meson: enable -Wunterminated-string-initialization

With af1a6db, now we can build with the
option.

(cherry picked from commit f548bc4)
(cherry picked from commit 7725496)
(cherry picked from commit da229ea)
(cherry picked from commit fbc4335)

Author: yuwata

meson.build

@@ -389,6 +389,7 @@ possible_common_cc_flags = [
         '-Wstrict-aliasing=2',
         '-Wstrict-prototypes',
         '-Wsuggest-attribute=noreturn',
+        '-Wunterminated-string-initialization',
         '-Wunused-function',
         '-Wwrite-strings',
         '-Wzero-length-bounds',