pkg: write dependencies directly file instead of buffer

So we don't get artificial limits on the amount of dependencies
(fixes #8).

src/apk_package.h

@@ -68,6 +68,7 @@ void apk_deps_parse(struct apk_database *db,
 		    apk_blob_t blob);
 int apk_deps_format(char *buf, int size,
 		    struct apk_dependency_array *depends);
+int apk_deps_write(struct apk_dependency_array *deps, struct apk_ostream *os);
 int apk_script_type(const char *name);
 
 struct apk_package *apk_pkg_new(void);

src/database.c

@@ -725,8 +725,6 @@ struct write_ctx {
 static int apk_db_write_config(struct apk_database *db)
 {
 	struct apk_ostream *os;
-	char buf[1024];
-	int n;
 
 	if (db->root == NULL)
 		return 0;
@@ -741,10 +739,8 @@ static int apk_db_write_config(struct apk_database *db)
 	os = apk_ostream_to_file("var/lib/apk/world", 0644);
 	if (os == NULL)
 		return -1;
-	n = apk_deps_format(buf, sizeof(buf), db->world);
-	if (n < sizeof(buf))
-		buf[n++] = '\n';
-	os->write(os, buf, n);
+	apk_deps_write(db->world, os);
+	os->write(os, "\n", 1);
 	os->close(os);
 
 	os = apk_ostream_to_file("var/lib/apk/installed.new", 0644);

src/package.c

@@ -149,6 +149,29 @@ int apk_deps_format(char *buf, int size,
 	return n;
 }
 
+int apk_deps_write(struct apk_dependency_array *deps, struct apk_ostream *os)
+{
+	int i, len, n = 0;
+
+	if (deps == NULL)
+		return 0;
+
+	for (i = 0; i < deps->num; i++) {
+		if (i) {
+			if (os->write(os, " ", 1) != 1)
+				return -1;
+			n += 1;
+		}
+
+		len = strlen(deps->item[i].name->name);
+		if (os->write(os, deps->item[i].name->name, len) != len)
+			return -1;
+		n += len;
+	}
+
+	return n;
+}
+
 static const char *script_types[] = {
 	[APK_SCRIPT_PRE_INSTALL]	= "pre-install",
 	[APK_SCRIPT_POST_INSTALL]	= "post-install",