MINOR: uri_normalizer: Add a `percent-decode-unreserved` normalizer

This normalizer decodes percent encoded characters within the RFC 3986
unreserved set.

See GitHub Issue #714.
diff --git a/src/http_act.c b/src/http_act.c
index df2bbe4..58e1bb8 100644
--- a/src/http_act.c
+++ b/src/http_act.c
@@ -302,6 +302,24 @@
 
 			break;
 		}
+		case ACT_NORMALIZE_URI_PERCENT_DECODE_UNRESERVED:
+		case ACT_NORMALIZE_URI_PERCENT_DECODE_UNRESERVED_STRICT: {
+			const struct ist path = http_get_path(uri);
+			struct ist newpath = ist2(replace->area, replace->size);
+
+			if (!isttest(path))
+				goto leave;
+
+			err = uri_normalizer_percent_decode_unreserved(path, rule->action == ACT_NORMALIZE_URI_PERCENT_DECODE_UNRESERVED_STRICT, &newpath);
+
+			if (err != URI_NORMALIZER_ERR_NONE)
+				break;
+
+			if (!http_replace_req_path(htx, newpath, 1))
+				goto fail_rewrite;
+
+			break;
+		}
 	}
 
 	switch (err) {
@@ -407,6 +425,21 @@
 			return ACT_RET_PRS_ERR;
 		}
 	}
+	else if (strcmp(args[cur_arg], "percent-decode-unreserved") == 0) {
+		cur_arg++;
+
+		if (strcmp(args[cur_arg], "strict") == 0) {
+			cur_arg++;
+			rule->action = ACT_NORMALIZE_URI_PERCENT_DECODE_UNRESERVED_STRICT;
+		}
+		else if (!*args[cur_arg]) {
+			rule->action = ACT_NORMALIZE_URI_PERCENT_DECODE_UNRESERVED;
+		}
+		else if (strcmp(args[cur_arg], "if") != 0 && strcmp(args[cur_arg], "unless") != 0) {
+			memprintf(err, "unknown argument '%s' for 'percent-decode-unreserved' normalizer", args[cur_arg]);
+			return ACT_RET_PRS_ERR;
+		}
+	}
 	else {
 		memprintf(err, "unknown normalizer '%s'", args[cur_arg]);
 		return ACT_RET_PRS_ERR;