iovec-util: make IOVEC_INCREMENT a regular function too

Even more than with the previous commit, this is not a trivial function
and there's no reason to believe this will actually be inlined nor that
it would be beneficial.

src/basic/iovec-util.c

@@ -14,6 +14,31 @@ size_t iovec_total_size(const struct iovec *i, size_t n) {
         return sum;
 }
 
+bool iovec_increment(struct iovec *i, size_t n, size_t k) {
+        assert(i || n == 0);
+
+        /* Returns true if there is nothing else to send (bytes written cover all of the iovec),
+         * false if there's still work to do. */
+
+        FOREACH_ARRAY(j, i, n) {
+                size_t sub;
+
+                if (j->iov_len == 0)
+                        continue;
+                if (k == 0)
+                        return false;
+
+                sub = MIN(j->iov_len, k);
+                j->iov_len -= sub;
+                j->iov_base = (uint8_t*) j->iov_base + sub;
+                k -= sub;
+        }
+
+        assert(k == 0); /* Anything else would mean that we wrote more bytes than available,
+                         * or the kernel reported writing more bytes than sent. */
+        return true;
+}
+
 char* set_iovec_string_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value) {
         char *x;
 

src/basic/iovec-util.h

@@ -9,28 +9,7 @@
 
 size_t iovec_total_size(const struct iovec *i, size_t n);
 
-static inline bool IOVEC_INCREMENT(struct iovec *i, size_t n, size_t k) {
-        /* Returns true if there is nothing else to send (bytes written cover all of the iovec),
-         * false if there's still work to do. */
-
-        for (size_t j = 0; j < n; j++) {
-                size_t sub;
-
-                if (i[j].iov_len == 0)
-                        continue;
-                if (k == 0)
-                        return false;
-
-                sub = MIN(i[j].iov_len, k);
-                i[j].iov_len -= sub;
-                i[j].iov_base = (uint8_t*) i[j].iov_base + sub;
-                k -= sub;
-        }
-
-        assert(k == 0); /* Anything else would mean that we wrote more bytes than available,
-                         * or the kernel reported writing more bytes than sent. */
-        return true;
-}
+bool iovec_increment(struct iovec *i, size_t n, size_t k);
 
 #define IOVEC_NULL (const struct iovec) {}
 

src/basic/log.c

@@ -541,7 +541,7 @@ static int write_to_syslog(
                 if (!syslog_is_stream)
                         break;
 
-                if (IOVEC_INCREMENT(iovec, ELEMENTSOF(iovec), n))
+                if (iovec_increment(iovec, ELEMENTSOF(iovec), n))
                         break;
         }