lib-sieve: Cleaned up object definitions using newer C99 syntax.

src/lib-sieve/cmp-i-ascii-casemap.c

src/lib-sieve/cmp-i-octet.c

src/lib-sieve/mcht-contains.c

src/lib-sieve/mcht-is.c

src/lib-sieve/mcht-matches.c

...gins/comparator-i-ascii-numeric/ext-cmp-i-ascii-numeric.c

src/lib-sieve/plugins/copy/ext-copy.c

src/lib-sieve/plugins/include/ext-include-variables.c

src/lib-sieve/plugins/mailbox/tag-mailbox-create.c

src/lib-sieve/plugins/regex/mcht-regex.c

src/lib-sieve/plugins/relational/mcht-count.c

src/lib-sieve/plugins/relational/mcht-value.c

src/lib-sieve/plugins/subaddress/ext-subaddress.c

...s/vnd.dovecot/environment/ext-vnd-environment-variables.c

src/lib-sieve/sieve-address-parts.c

src/lib-sieve/sieve-objects.h

src/testsuite/testsuite-objects.c

src/testsuite/testsuite-substitutions.c