compilation warnings on extension

With my nice new compiler, we now get some compilation warnings on php-ext-couchbase. None look critical, but should be reviewed.

cc -I. -I/Users/ingenthr/src/php-ext-couchbase -DPHP_ATOM_INC -I/Users/ingenthr/src/php-ext-couchbase/include -I/Users/ingenthr/src/php-ext-couchbase/main -I/Users/ingenthr/src/php-ext-couchbase -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /Users/ingenthr/src/php-ext-couchbase/replica.c -fno-common -DPIC -o .libs/replica.o
/Users/ingenthr/src/php-ext-couchbase/replica.c:41:9: warning: passing 'const void *' to parameter of type 'void *'
discards qualifiers [-Wincompatible-pointer-types]
free(ret->data.v.v0.key);
^~~~~~~~~~~~~~~~~~
/usr/include/stdlib.h:160:18: note: passing argument to parameter here
void free(void *);
^
/Users/ingenthr/src/php-ext-couchbase/replica.c:42:9: warning: passing 'const void *' to parameter of type 'void *'
discards qualifiers [-Wincompatible-pointer-types]
free(ret->data.v.v0.bytes);
^~~~~~~~~~~~~~~~~~~~
/usr/include/stdlib.h:160:18: note: passing argument to parameter here
void free(void *);
^
/Users/ingenthr/src/php-ext-couchbase/replica.c:46:10: warning: passing 'const void *' to parameter of type 'void *'
discards qualifiers [-Wincompatible-pointer-types]
memcpy(ret->data.v.v0.key, r->v.v0.key, ret->data.v.v0.nkey);
^~~~~~~~~~~~~~~~~~
/usr/include/secure/_string.h:55:30: note: expanded from macro 'memcpy'
? _builtin__memcpy_chk (dest, src, len, __darwin_obsz0 (dest)) \
^
/Users/ingenthr/src/php-ext-couchbase/replica.c:46:10: warning: passing 'const void *' to parameter of type 'void *'
discards qualifiers [-Wincompatible-pointer-types]
memcpy(ret->data.v.v0.key, r->v.v0.key, ret->data.v.v0.nkey);
^~~~~~~~~~~~~~~~~~
/usr/include/secure/_string.h:56:27: note: expanded from macro 'memcpy'
: __inline_memcpy_chk (dest, src, len))
^
/usr/include/secure/string.h:59:28: note: passing argument to parameter '_dest' here
_inline_memcpy_chk (void *dest, const void *_src, size_t __len)
^
/Users/ingenthr/src/php-ext-couchbase/replica.c:47:10: warning: passing 'const void *' to parameter of type 'void *'
discards qualifiers [-Wincompatible-pointer-types]
memcpy(ret->data.v.v0.bytes, r->v.v0.bytes, ret->data.v.v0.nbytes);
^~~~~~~~~~~~~~~~~~~~
/usr/include/secure/_string.h:55:30: note: expanded from macro 'memcpy'
? _builtin__memcpy_chk (dest, src, len, __darwin_obsz0 (dest)) \
^
/Users/ingenthr/src/php-ext-couchbase/replica.c:47:10: warning: passing 'const void *' to parameter of type 'void *'
discards qualifiers [-Wincompatible-pointer-types]
memcpy(ret->data.v.v0.bytes, r->v.v0.bytes, ret->data.v.v0.nbytes);
^~~~~~~~~~~~~~~~~~~~
/usr/include/secure/_string.h:56:27: note: expanded from macro 'memcpy'
: __inline_memcpy_chk (dest, src, len))
^
/usr/include/secure/string.h:59:28: note: passing argument to parameter '_dest' here
_inline_memcpy_chk (void *dest, const void *_src, size_t __len)
^
/Users/ingenthr/src/php-ext-couchbase/replica.c:142:32: warning: passing 'const char *' to parameter of type 'char *'
discards qualifiers [-Wincompatible-pointer-types]
add_assoc_string(r, "error", lcb_strerror(NULL, e->error), 1);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/php/Zend/zend_API.h:371:111: note: expanded from macro 'add_assoc_string'
..._key, __str, __duplicate) add_assoc_string_ex(arg, __key, strlen(_key)+1, __str, __duplicate)
^
/usr/include/php/Zend/zend_API.h:362:82: note: passing argument to parameter 'str' here
ZEND_API int add_assoc_string_ex(zval *arg, const char *key, uint key_len, char *str, int duplicate);
^
/Users/ingenthr/src/php-ext-couchbase/replica.c:358:56: warning: passing 'lcb_get_replica_cmd_t **'
(aka 'struct lcb_get_replica_cmd_st **') to parameter of type 'const lcb_get_replica_cmd_t *const *' (aka 'const
struct lcb_get_replica_cmd_st *const *') discards qualifiers in nested pointer types [-Wincompatible-pointer-types]
retval = lcb_get_replica(instance, &cookie, num_docs, commands);
^~~~~~~~
/usr/local/include/libcouchbase/couchbase.h:314:69: note: passing argument to parameter 'commands' here
const lcb_get_replica_cmd_t *const *commands);
^