Section needs to be explicitly defined

The absence of value between the section parentheses resulted in the
section being 0 (header files), which is unlikely to be the one wanted

src/main.c

@@ -24,7 +24,7 @@ static int parse_section(struct parser *p) {
 			int ret = str_append_ch(section, ch);
 			assert(ret != -1);
 		} else if (ch == ')') {
-			if (!section->str) {
+			if (section->len == 0) {
 				break;
 			}
 			int sec = strtol(section->str, NULL, 10);

test/preamble

@@ -13,6 +13,12 @@ test
 EOF
 end 1
 
+begin "Expects a section within the parentheses"
+scdoc <<EOF >/dev/null
+test()
+EOF
+end 1
+
 begin "Expects name to alphanumeric"
 scdoc <<EOF >/dev/null
 !!!!(8)