GUACAMOLE-407: As the Docker base image lacks the "en_US" locale, we must instead use "C.UTF-8" to ensure characters render correctly.
diff --git a/Dockerfile b/Dockerfile
index dc58765..4d463a3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -84,7 +84,7 @@
 ARG PREFIX_DIR=/usr/local/guacamole
 
 # Runtime environment
-ENV LC_ALL=en_US.UTF-8
+ENV LC_ALL=C.UTF-8
 ENV LD_LIBRARY_PATH=${PREFIX_DIR}/lib
 ENV GUACD_LOG_LEVEL=info