diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8e00482f..50e2f6b1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,6 +3,7 @@ cmake_policy(SET CMP0048 NEW)
 
 project(ttyd VERSION "1.4.0")
 
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_GNU_SOURCE")
 if(CMAKE_VERSION VERSION_LESS "3.1")
     if ("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU")
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99")
diff --git a/src/http.c b/src/http.c
index d569ce97..522ecf03 100644
--- a/src/http.c
+++ b/src/http.c
@@ -1,3 +1,6 @@
+#include <string.h>
+#include <libwebsockets.h>
+
 #include "server.h"
 #include "html.h"
 
@@ -98,7 +101,7 @@ callback_http(struct lws *wsi, enum lws_callback_reasons reason, void *user, voi
                 goto try_to_reuse;
             }
 
-            if (strncmp((const char *) in, "/", 1)) {
+            if (strncmp((const char *) in, "/", 1) != 0) {
                 lws_return_http_status(wsi, HTTP_STATUS_NOT_FOUND, NULL);
                 goto try_to_reuse;
             }
diff --git a/src/protocol.c b/src/protocol.c
index 19746536..21074d53 100644
--- a/src/protocol.c
+++ b/src/protocol.c
@@ -1,4 +1,30 @@
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/queue.h>
+#include <sys/select.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <pthread.h>
+
+#if defined(__OpenBSD__) || defined(__APPLE__)
+#include <util.h>
+#elif defined(__FreeBSD__)
+#include <libutil.h>
+#else
+#include <pty.h>
+#endif
+
+#include <libwebsockets.h>
+#include <json.h>
+
 #include "server.h"
+#include "utils.h"
 
 int
 send_initial_message(struct lws *wsi) {
diff --git a/src/server.c b/src/server.c
index a16bab0d..b8d0a3be 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1,4 +1,25 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <getopt.h>
+#include <pthread.h>
+#include <signal.h>
+#include <sys/stat.h>
+
+#ifdef HAVE_LWS_CONFIG_H
+#include "lws_config.h"
+#endif
+#include <libwebsockets.h>
+#include <json.h>
+
 #include "server.h"
+#include "utils.h"
+
+#ifndef TTYD_VERSION
+#define TTYD_VERSION "unknown"
+#endif
 
 volatile bool force_exit = false;
 struct lws_context *context;
diff --git a/src/server.h b/src/server.h
index e1c64696..5e61d2a2 100644
--- a/src/server.h
+++ b/src/server.h
@@ -1,54 +1,6 @@
-#ifdef HAVE_LWS_CONFIG_H
-#include "lws_config.h"
-#endif
-
-#ifndef TTYD_VERSION
-#define TTYD_VERSION "unknown"
-#endif
-
-#define _GNU_SOURCE
-
-#include <stdio.h>
-#include <stdlib.h>
 #include <stdbool.h>
-#include <signal.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <fcntl.h>
-#include <getopt.h>
-#include <pthread.h>
 #include <sys/ioctl.h>
 #include <sys/queue.h>
-#include <sys/stat.h>
-#include <sys/select.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <assert.h>
-
-#ifdef __OpenBSD__
-#define STAILQ_HEAD            SIMPLEQ_HEAD
-#define STAILQ_ENTRY           SIMPLEQ_ENTRY
-#define STAILQ_INIT            SIMPLEQ_INIT
-#define STAILQ_INSERT_TAIL     SIMPLEQ_INSERT_TAIL
-#define STAILQ_EMPTY           SIMPLEQ_EMPTY
-#define STAILQ_FIRST           SIMPLEQ_FIRST
-#define STAILQ_REMOVE_HEAD     SIMPLEQ_REMOVE_HEAD
-#define STAILQ_FOREACH         SIMPLEQ_FOREACH
-#endif
-
-#if defined(__OpenBSD__) || defined(__APPLE__)
-#include <util.h>
-#elif defined(__FreeBSD__)
-#include <libutil.h>
-#else
-#include <pty.h>
-#endif
-
-#include <libwebsockets.h>
-#include <json.h>
-
-#include "utils.h"
 
 // client message
 #define INPUT '0'
diff --git a/src/utils.c b/src/utils.c
index ac16bd15..c4330ef9 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -1,5 +1,3 @@
-#define _GNU_SOURCE
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdbool.h>