diff --git a/libgimpconfig/gimpcolorconfig.h b/libgimpconfig/gimpcolorconfig.h
index 39c1bf7053..e871c75a14 100644
--- a/libgimpconfig/gimpcolorconfig.h
+++ b/libgimpconfig/gimpcolorconfig.h
@@ -19,18 +19,16 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_COLOR_CONFIG_H__
+#define __GIMP_COLOR_CONFIG_H__
+
 
 #define GIMP_TYPE_COLOR_CONFIG (gimp_color_config_get_type ())
-G_DECLARE_FINAL_TYPE (GimpColorConfig,
-                      gimp_color_config,
-                      GIMP, COLOR_CONFIG,
-                      GObject)
+G_DECLARE_FINAL_TYPE (GimpColorConfig, gimp_color_config, GIMP, COLOR_CONFIG, GObject)
 
 
 GimpColorManagementMode
@@ -60,3 +58,5 @@ GimpColorProfile * gimp_color_config_get_display_color_profile    (GimpColorConf
 GimpColorProfile * gimp_color_config_get_simulation_color_profile (GimpColorConfig  *config,
                                                                    GError          **error);
 
+
+#endif /* GIMP_COLOR_CONFIG_H__ */
diff --git a/libgimpconfig/gimpconfig-deserialize.h b/libgimpconfig/gimpconfig-deserialize.h
index 1671ded830..271a20d301 100644
--- a/libgimpconfig/gimpconfig-deserialize.h
+++ b/libgimpconfig/gimpconfig-deserialize.h
@@ -19,12 +19,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_DESERIALIZE_H__
+#define __GIMP_CONFIG_DESERIALIZE_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
@@ -37,4 +38,7 @@ GTokenType  gimp_config_deserialize_property   (GimpConfig *config,
                                                 GScanner   *scanner,
                                                 gint        nest_level);
 
+
 G_END_DECLS
+
+#endif /* __GIMP_CONFIG_DESERIALIZE_H__ */
diff --git a/libgimpconfig/gimpconfig-error.h b/libgimpconfig/gimpconfig-error.h
index b88d7d002c..a20884e37e 100644
--- a/libgimpconfig/gimpconfig-error.h
+++ b/libgimpconfig/gimpconfig-error.h
@@ -18,12 +18,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_ERROR_H__
+#define __GIMP_CONFIG_ERROR_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
@@ -50,7 +51,9 @@ typedef enum
 
 #define GIMP_CONFIG_ERROR (gimp_config_error_quark ())
 
-GQuark   gimp_config_error_quark (void) G_GNUC_CONST;
+GQuark        gimp_config_error_quark   (void) G_GNUC_CONST;
+
 
 G_END_DECLS
 
+#endif  /* __GIMP_CONFIG_ERROR_H__ */
diff --git a/libgimpconfig/gimpconfig-iface.h b/libgimpconfig/gimpconfig-iface.h
index 6f0cf8b7cd..c142ee6c52 100644
--- a/libgimpconfig/gimpconfig-iface.h
+++ b/libgimpconfig/gimpconfig-iface.h
@@ -19,23 +19,19 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_IFACE_H__
+#define __GIMP_CONFIG_IFACE_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
 
-
 #define GIMP_TYPE_CONFIG (gimp_config_get_type ())
-G_DECLARE_INTERFACE (GimpConfig,
-                     gimp_config,
-                     GIMP, CONFIG,
-                     GObject)
-
+G_DECLARE_INTERFACE (GimpConfig, gimp_config, GIMP, CONFIG, GObject)
 
 struct _GimpConfigInterface
 {
@@ -133,4 +129,7 @@ gboolean   gimp_config_copy                  (GimpConfig          *src,
                                               GimpConfig          *dest,
                                               GParamFlags          flags);
 
+
 G_END_DECLS
+
+#endif  /* __GIMP_CONFIG_IFACE_H__ */
diff --git a/libgimpconfig/gimpconfig-params.h b/libgimpconfig/gimpconfig-params.h
index 5ae0a19a93..a11175d769 100644
--- a/libgimpconfig/gimpconfig-params.h
+++ b/libgimpconfig/gimpconfig-params.h
@@ -20,12 +20,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_PARAMS_H__
+#define __GIMP_CONFIG_PARAMS_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
@@ -227,4 +228,7 @@ G_BEGIN_DECLS
 
 GParamSpec * gimp_config_param_spec_duplicate (GParamSpec *pspec);
 
+
 G_END_DECLS
+
+#endif /* __GIMP_CONFIG_PARAMS_H__ */
diff --git a/libgimpconfig/gimpconfig-path.h b/libgimpconfig/gimpconfig-path.h
index dd9710fb45..f6dff2a1aa 100644
--- a/libgimpconfig/gimpconfig-path.h
+++ b/libgimpconfig/gimpconfig-path.h
@@ -19,12 +19,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_PATH_H__
+#define __GIMP_CONFIG_PATH_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
@@ -102,5 +103,7 @@ gchar             * gimp_config_build_writable_path  (const gchar  *name) G_GNUC
 gchar             * gimp_config_build_plug_in_path   (const gchar  *name) G_GNUC_MALLOC;
 gchar             * gimp_config_build_system_path    (const gchar  *name) G_GNUC_MALLOC;
 
+
 G_END_DECLS
 
+#endif /* __GIMP_CONFIG_PATH_H__ */
diff --git a/libgimpconfig/gimpconfig-register.h b/libgimpconfig/gimpconfig-register.h
index e7e8608b5d..9cfd722a45 100644
--- a/libgimpconfig/gimpconfig-register.h
+++ b/libgimpconfig/gimpconfig-register.h
@@ -19,12 +19,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_REGISTER_H__
+#define __GIMP_CONFIG_REGISTER_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
@@ -35,4 +36,7 @@ GType   gimp_config_type_register (GType         parent_type,
                                    GParamSpec  **pspecs,
                                    gint          n_pspecs);
 
+
 G_END_DECLS
+
+#endif /* __GIMP_CONFIG_REGISTER_H__ */
diff --git a/libgimpconfig/gimpconfig-serialize.h b/libgimpconfig/gimpconfig-serialize.h
index 58de1ddfb3..c25ab3b391 100644
--- a/libgimpconfig/gimpconfig-serialize.h
+++ b/libgimpconfig/gimpconfig-serialize.h
@@ -19,12 +19,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_SERIALIZE_H__
+#define __GIMP_CONFIG_SERIALIZE_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
@@ -45,5 +46,7 @@ gboolean  gimp_config_serialize_value              (const GValue     *value,
                                                     GString          *str,
                                                     gboolean          escaped);
 
+
 G_END_DECLS
 
+#endif /* __GIMP_CONFIG_SERIALIZE_H__ */
diff --git a/libgimpconfig/gimpconfig-utils.h b/libgimpconfig/gimpconfig-utils.h
index f19cee39ad..6975b64170 100644
--- a/libgimpconfig/gimpconfig-utils.h
+++ b/libgimpconfig/gimpconfig-utils.h
@@ -19,12 +19,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_UTILS_H__
+#define __GIMP_CONFIG_UTILS_H__
+
 G_BEGIN_DECLS
 
 /* For information look into the C source or the html documentation */
@@ -45,4 +46,7 @@ void       gimp_config_reset_property        (GObject      *object,
 void       gimp_config_string_append_escaped (GString      *string,
                                               const gchar  *val);
 
+
 G_END_DECLS
+
+#endif  /* __GIMP_CONFIG_UTILS_H__ */
diff --git a/libgimpconfig/gimpconfig.h b/libgimpconfig/gimpconfig.h
index 7950522a08..43cbf37ddb 100644
--- a/libgimpconfig/gimpconfig.h
+++ b/libgimpconfig/gimpconfig.h
@@ -16,7 +16,8 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
+#ifndef __GIMP_CONFIG_H__
+#define __GIMP_CONFIG_H__
 
 #include <gegl.h>
 
@@ -40,3 +41,5 @@
 #include <libgimpconfig/gimpcolorconfig.h>
 
 #undef __GIMP_CONFIG_H_INSIDE__
+
+#endif  /* __GIMP_CONFIG_H__ */
diff --git a/libgimpconfig/gimpconfigenums.h b/libgimpconfig/gimpconfigenums.h
index 0eb9d37156..562085021c 100644
--- a/libgimpconfig/gimpconfigenums.h
+++ b/libgimpconfig/gimpconfigenums.h
@@ -19,7 +19,8 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
+#ifndef __GIMP_CONFIG_ENUMS_H__
+#define __GIMP_CONFIG_ENUMS_H__
 
 
 #define GIMP_TYPE_COLOR_MANAGEMENT_MODE (gimp_color_management_mode_get_type ())
@@ -62,3 +63,6 @@ typedef enum
   GIMP_COLOR_RENDERING_INTENT_SATURATION,            /*< desc="Saturation"            >*/
   GIMP_COLOR_RENDERING_INTENT_ABSOLUTE_COLORIMETRIC  /*< desc="Absolute colorimetric" >*/
 } GimpColorRenderingIntent;
+
+
+#endif /* __GIMP_CONFIG_ENUMS_H__ */
diff --git a/libgimpconfig/gimpconfigtypes.h b/libgimpconfig/gimpconfigtypes.h
index 0260477054..be36713935 100644
--- a/libgimpconfig/gimpconfigtypes.h
+++ b/libgimpconfig/gimpconfigtypes.h
@@ -19,7 +19,9 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
+#ifndef __GIMP_CONFIG_TYPES_H__
+#define __GIMP_CONFIG_TYPES_H__
+
 
 #include <libgimpbase/gimpbasetypes.h>
 
@@ -32,3 +34,6 @@ typedef struct _GScanner          GimpScanner;
 typedef struct _GimpColorConfig   GimpColorConfig;
 
 #include <libgimpconfig/gimpconfigenums.h>
+
+
+#endif  /* __GIMP_CONFIG_TYPES_H__ */
diff --git a/libgimpconfig/gimpconfigwriter.h b/libgimpconfig/gimpconfigwriter.h
index 4ff27830a0..5e60fa3427 100644
--- a/libgimpconfig/gimpconfigwriter.h
+++ b/libgimpconfig/gimpconfigwriter.h
@@ -19,12 +19,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_CONFIG_WRITER_H__
+#define __GIMP_CONFIG_WRITER_H__
+
 
 /**
  * GIMP_TYPE_CONFIG_WRITER:
@@ -80,3 +81,6 @@ void               gimp_config_writer_close        (GimpConfigWriter  *writer);
 gboolean           gimp_config_writer_finish       (GimpConfigWriter  *writer,
                                                     const gchar       *footer,
                                                     GError           **error);
+
+
+#endif /* __GIMP_CONFIG_WRITER_H__ */
diff --git a/libgimpconfig/gimpscanner.h b/libgimpconfig/gimpscanner.h
index 753b789f44..e690c9be2e 100644
--- a/libgimpconfig/gimpscanner.h
+++ b/libgimpconfig/gimpscanner.h
@@ -20,12 +20,13 @@
  * <https://www.gnu.org/licenses/>.
  */
 
-#pragma once
-
 #if !defined (__GIMP_CONFIG_H_INSIDE__) && !defined (GIMP_CONFIG_COMPILATION)
 #error "Only <libgimpconfig/gimpconfig.h> can be included directly."
 #endif
 
+#ifndef __GIMP_SCANNER_H__
+#define __GIMP_SCANNER_H__
+
 
 /**
  * GIMP_TYPE_SCANNER:
@@ -74,3 +75,6 @@ gboolean      gimp_scanner_parse_color              (GimpScanner   *scanner,
                                                      GeglColor    **color);
 gboolean      gimp_scanner_parse_matrix2            (GimpScanner   *scanner,
                                                      GimpMatrix2   *dest);
+
+
+#endif /* __GIMP_SCANNER_H__ */