Restore rounded variable declaration removed by mistake

The previous commit (suggestion from GitHub UI) accidentally removed
the declaration and computation of the 'rounded' variable while keeping
its usage, causing a compilation error.

Author: lacatoire

ext/standard/formatted_print.c

@@ -268,6 +268,13 @@ php_sprintf_appenddouble(zend_string **buffer, size_t *pos,
 						&is_negative, &num_buf[1], &s_len);
 			/* Prevent negative sign when value rounds to zero (GH-12237) */
 			if (is_negative) {
+				double rounded;
+				if (fmt == 'f' || fmt == 'F') {
+					double factor = pow(10.0, (double)precision);
+					rounded = round(fabs(number) * factor) / factor;
+				} else {
+					rounded = fabs(number);
+				}
 				if (rounded == 0.0) {
 					is_negative = false;
 				}