diff --git a/common/str.cpp b/common/str.cpp
index 2ae366bca8e..77a50bd768f 100644
--- a/common/str.cpp
+++ b/common/str.cpp
@@ -1323,3 +1323,22 @@ char *scumm_strdup(const char *in) {
 	}
 	return out;
 }
+
+//  Portable implementation of strcasestr.
+const char *scumm_strcasestr(const char *s, const char *find) {
+	char c, sc;
+	size_t len;
+
+	if ((c = *find++) != 0) {
+		c = (char)tolower((unsigned char)c);
+		len = strlen(find);
+		do {
+			do {
+				if ((sc = *s++) == 0)
+					return (NULL);
+			} while ((char)tolower((unsigned char)sc) != c);
+		} while (scumm_strnicmp(s, find, len) != 0);
+		s--;
+	}
+	return s;
+}
diff --git a/common/str.h b/common/str.h
index c19b2ef6999..bce55fd2103 100644
--- a/common/str.h
+++ b/common/str.h
@@ -568,4 +568,6 @@ extern char *scumm_strdup(const char *in);
 extern int scumm_compareDictionary(const char *s1, const char *s2);
 extern const char *scumm_skipArticle(const char *s1);
 
+extern const char *scumm_strcasestr(const char *s, const char *find);
+
 #endif