Fix building on musl libc.

src/client/linux/crash_generation/crash_generation_server.cc

Index: src/client/linux/crash_generation/crash_generation_server.cc
diff --git a/src/client/linux/crash_generation/crash_generation_server.cc b/src/client/linux/crash_generation/crash_generation_server.cc
index 1d7d93b99cb4e749dafbe21c26df84f5c78ef4e9..0f20d5be400b1a7ae237f370990e3aa3e7bdb12a 100644
--- a/src/client/linux/crash_generation/crash_generation_server.cc
+++ b/src/client/linux/crash_generation/crash_generation_server.cc
@@ -28,7 +28,6 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <assert.h>
-#include <dirent.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <poll.h>
@@ -49,6 +48,8 @@
 #include "common/linux/guid_creator.h"
 #include "common/linux/safe_readlink.h"
 
+#include <dirent.h>
+
 static const char kCommandQuit = 'x';
 
 namespace google_breakpad {