Fix building with gcc-4.7

https://bugs.gentoo.org/show_bug.cgi?id=421867

Patch written by LE GARREC Vincent <legarrec.vincent@gmail.com>
--- a/src/objects/tool_object.cpp
+++ b/src/objects/tool_object.cpp
@@ -50,6 +50,7 @@ stopProcess()
 #include <QKeySequence>
 #include <QString>
 #include <QStringList>
+#include <unistd.h>              // usleep
 
 
 #if 1
--- a/src/utils/vk_config.cpp
+++ b/src/utils/vk_config.cpp
@@ -25,6 +25,8 @@
 #include "utils/vk_utils.h"
 
 #include <pwd.h>     // getpwuid
+#include <sys/types.h>         // getuid
+#include <unistd.h>            // getuid
 
 #include <QColor>
 #include <QDir>
--- a/src/utils/vk_utils.cpp
+++ b/src/utils/vk_utils.cpp
@@ -22,6 +22,8 @@
 #include "utils/vk_config.h"        // vkname()
 
 #include <cstdlib>                  // exit, mkstemp, free/malloc, etc
+#include <sys/types.h>              // getpid
+#include <unistd.h>                 // getpid
 
 #include <QDateTime>
 #include <QFile>