Snippets for m17n-lib 1.8.6 from Alpine armv7

Sourced from https://build.alpinelinux.org/buildlogs/build-edge-armv7/community/m17n-lib/m17n-lib-1.8.6-r1.log.

• mtext-wseg.c:129:3: warning: 'th_brk' is deprecated: Use 'th_brk_find_breaks' instead [-Wdeprecated-declarations]
    129 |   int count = th_brk ((thchar_t *) tis, breaks, len);
        |   ^~~