diff --git a/src/config.h.in b/src/config.h.in
index b2ebaef..2f210d7 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -1,5 +1,5 @@
-#ifndef __CONFIG_H
-#define __CONFIG_H
+#ifndef SOLVESPACE_CONFIG_H
+#define SOLVESPACE_CONFIG_H
 
 #define PACKAGE_VERSION "@solvespace_VERSION_MAJOR@.@solvespace_VERSION_MINOR@~@solvespace_GIT_HASH@"
 
diff --git a/src/dsc.h b/src/dsc.h
index bd5c7f3..3425082 100644
--- a/src/dsc.h
+++ b/src/dsc.h
@@ -4,8 +4,8 @@
 //
 // Copyright 2008-2013 Jonathan Westhues.
 //-----------------------------------------------------------------------------
-#ifndef __DSC_H
-#define __DSC_H
+#ifndef SOLVESPACE_DSC_H
+#define SOLVESPACE_DSC_H
 
 #include "solvespace.h"
 
@@ -308,7 +308,7 @@ public:
         if(n >= elemsAllocated) {
             ReserveMore((elemsAllocated + 32)*2 - n);
         }
-    
+
         int first = 0, last = n;
         // We know that we must insert within the closed interval [first,last]
         while(first != last) {
diff --git a/src/expr.h b/src/expr.h
index ea11310..83ba23b 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -4,8 +4,8 @@
 //
 // Copyright 2008-2013 Jonathan Westhues.
 //-----------------------------------------------------------------------------
-#ifndef __EXPR_H
-#define __EXPR_H
+#ifndef SOLVESPACE_EXPR_H
+#define SOLVESPACE_EXPR_H
 
 class Expr {
 public:
diff --git a/src/polygon.h b/src/polygon.h
index e813ad9..9855a9d 100644
--- a/src/polygon.h
+++ b/src/polygon.h
@@ -5,8 +5,8 @@
 // Copyright 2008-2013 Jonathan Westhues.
 //-----------------------------------------------------------------------------
 
-#ifndef __POLYGON_H
-#define __POLYGON_H
+#ifndef SOLVESPACE_POLYGON_H
+#define SOLVESPACE_POLYGON_H
 
 class SPointList;
 class SPolygon;
diff --git a/src/sketch.h b/src/sketch.h
index 65cfd2e..33a9895 100644
--- a/src/sketch.h
+++ b/src/sketch.h
@@ -5,8 +5,8 @@
 // Copyright 2008-2013 Jonathan Westhues.
 //-----------------------------------------------------------------------------
 
-#ifndef __SKETCH_H
-#define __SKETCH_H
+#ifndef SOLVESPACE_SKETCH_H
+#define SOLVESPACE_SKETCH_H
 
 class hGroup;
 class hRequest;
diff --git a/src/solvespace.h b/src/solvespace.h
index 1306ae4..de4c39c 100644
--- a/src/solvespace.h
+++ b/src/solvespace.h
@@ -4,32 +4,31 @@
 // Copyright 2008-2013 Jonathan Westhues.
 //-----------------------------------------------------------------------------
 
-#ifndef __SOLVESPACE_H
-#define __SOLVESPACE_H
+#ifndef SOLVESPACE_H
+#define SOLVESPACE_H
 
-#include <stdint.h>
-#include <stdlib.h>
 #include <ctype.h>
-#include <string.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <stdarg.h>
-#include <setjmp.h>
+#include <limits.h>
 #include <math.h>
 #include <setjmp.h>
-#include <limits.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <algorithm>
+#include <chrono>
 #include <functional>
-#include <memory>
-#include <string>
 #include <locale>
-#include <vector>
+#include <map>
+#include <memory>
+#include <set>
+#include <sstream>
+#include <string>
 #include <unordered_map>
 #include <unordered_set>
-#include <map>
-#include <set>
-#include <chrono>
-#include <sstream>
+#include <vector>
 
 // We declare these in advance instead of simply using FT_Library
 // (defined as typedef FT_LibraryRec_* FT_Library) because including
diff --git a/src/srf/surface.h b/src/srf/surface.h
index 98ad820..42dd8ba 100644
--- a/src/srf/surface.h
+++ b/src/srf/surface.h
@@ -7,8 +7,8 @@
 // Copyright 2008-2013 Jonathan Westhues.
 //-----------------------------------------------------------------------------
 
-#ifndef __SURFACE_H
-#define __SURFACE_H
+#ifndef SOLVESPACE_SURFACE_H
+#define SOLVESPACE_SURFACE_H
 
 // Utility functions, Bernstein polynomials of order 1-3 and their derivatives.
 double Bernstein(int k, int deg, double t);
diff --git a/src/ttf.h b/src/ttf.h
index fe82fee..2eea016 100644
--- a/src/ttf.h
+++ b/src/ttf.h
@@ -6,8 +6,8 @@
 // Copyright 2016 whitequark, Peter Barfuss.
 //-----------------------------------------------------------------------------
 
-#ifndef __TTF_H
-#define __TTF_H
+#ifndef SOLVESPACE_TTF_H
+#define SOLVESPACE_TTF_H
 
 class TtfFont {
 public:
diff --git a/src/ui.h b/src/ui.h
index b5a6db4..0a86be6 100644
--- a/src/ui.h
+++ b/src/ui.h
@@ -5,8 +5,8 @@
 // Copyright 2008-2013 Jonathan Westhues.
 //-----------------------------------------------------------------------------
 
-#ifndef __UI_H
-#define __UI_H
+#ifndef SOLVESPACE_UI_H
+#define SOLVESPACE_UI_H
 
 class Locale {
 public: