diff --git a/libguac/Makefile.am b/libguac/Makefile.am
index 3c69a92d..ae919670 100644
--- a/libguac/Makefile.am
+++ b/libguac/Makefile.am
@@ -44,7 +44,7 @@ libguacinc_HEADERS = include/client.h include/socket.h include/protocol.h includ
 
 lib_LTLIBRARIES = libguac.la
 
-libguac_la_SOURCES = src/client.c src/socket.c src/protocol.c src/client-handlers.c src/error.c src/palette.c
+libguac_la_SOURCES = src/client.c src/socket.c src/protocol.c src/client-handlers.c src/error.c src/palette.c src/unicode.c
 
 libguac_la_LDFLAGS = -version-info 3:1:0
 
diff --git a/libguac/include/unicode.h b/libguac/include/unicode.h
index d9abd849..3364641e 100644
--- a/libguac/include/unicode.h
+++ b/libguac/include/unicode.h
@@ -38,6 +38,8 @@
 #ifndef _GUAC_UNICODE_H
 #define _GUAC_UNICODE_H
 
+#include <stddef.h>
+
 /**
  * Given the initial byte of a single UTF-8 character, returns the overall
  * byte size of the entire character.
diff --git a/libguac/src/unicode.c b/libguac/src/unicode.c
index de80c8ed..f634c10c 100644
--- a/libguac/src/unicode.c
+++ b/libguac/src/unicode.c
@@ -35,6 +35,8 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
+#include <stddef.h>
+
 #include "unicode.h"
 
 size_t guac_utf8_charsize(unsigned char c) {