diff --git a/internal-headers.patch b/internal-headers.patch
new file mode 100644
index 0000000..7e0a454
--- /dev/null
+++ b/internal-headers.patch
@@ -0,0 +1,72 @@
+Index: VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/Makefile.kmk
+===================================================================
+--- VirtualBox-5.1.26.orig/src/VBox/Additions/x11/vboxvideo/Makefile.kmk
++++ VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/Makefile.kmk
+@@ -23,6 +23,9 @@ vboxvideo_70_DEFS := \
+ ifeq ($(KBUILD_TARGET),solaris) # don't use .solaris or anything here.
+  vboxvideo_70_DEFS += __EXTENSIONS__  ## @todo Why this?
+ endif
++if1of ($(KBUILD_TARGET), linux)
++ vboxvideo_70_DEFS += _POSIX_SOURCE ## X requires POSIX extensions
++endif
+ vboxvideo_13_DEFS := $(vboxvideo_70_DEFS) VBOXVIDEO_13
+ vboxvideo_15_DEFS := \
+ 	$(vboxvideo_13_DEFS) NO_ANSIC PCIACCESS XSERVER_LIBPCIACCESS _XORG_SERVER_H_ _DIX_CONFIG_H_
+Index: VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/edid.c
+===================================================================
+--- VirtualBox-5.1.26.orig/src/VBox/Additions/x11/vboxvideo/edid.c
++++ VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/edid.c
+@@ -44,10 +44,6 @@
+  *    Dave Airlie <airlied@redhat.com>
+  */
+ 
+-#if XORG_VERSION_CURRENT >= 11900000
+-#include <bits/sigset.h>
+-typedef __sigset_t sigset_t;
+-#endif
+ #include <misc.h>
+ #include <xf86DDC.h>
+ #include <xf86Crtc.h>
+Index: VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/pointer.c
+===================================================================
+--- VirtualBox-5.1.26.orig/src/VBox/Additions/x11/vboxvideo/pointer.c
++++ VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/pointer.c
+@@ -15,10 +15,6 @@
+  * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+  */
+ 
+-#if XORG_VERSION_CURRENT >= 11900000
+-#include <bits/sigset.h>
+-typedef __sigset_t sigset_t;
+-#endif
+ #include <VBox/VBoxGuestLib.h>
+ 
+ #ifndef PCIACCESS
+Index: VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/vboxvideo.h
+===================================================================
+--- VirtualBox-5.1.26.orig/src/VBox/Additions/x11/vboxvideo/vboxvideo.h
++++ VirtualBox-5.1.26/src/VBox/Additions/x11/vboxvideo/vboxvideo.h
+@@ -52,10 +52,6 @@
+ #ifndef _VBOXVIDEO_H_
+ #define _VBOXVIDEO_H_
+ 
+-#if XORG_VERSION_CURRENT >= 11900000
+-#include <bits/sigset.h>
+-typedef __sigset_t sigset_t;
+-#endif
+ #include <VBox/VBoxVideoGuest.h>
+ #include <VBox/VBoxVideo.h>
+ #include "version-generated.h"
+Index: VirtualBox-5.1.26/src/VBox/ExtPacks/VBoxDTrace/Makefile.kmk
+===================================================================
+--- VirtualBox-5.1.26.orig/src/VBox/ExtPacks/VBoxDTrace/Makefile.kmk
++++ VirtualBox-5.1.26/src/VBox/ExtPacks/VBoxDTrace/Makefile.kmk
+@@ -103,7 +103,7 @@ if defined(VBOX_WITH_EXTPACK_VBOXDTRACE)
+  VBoxDTraceCmd_TEMPLATE = VBoxR3ExtPackDTrace
+  VBoxDTraceCmd_DEFS = RTMEM_WRAP_TO_EF_APIS VBOX_EXTPACK_VBOXDTRACE_MANGLED_NAME=\"$(VBOX_EXTPACK_VBOXDTRACE_MANGLED_NAME)\"
+  #VBoxDTraceCmd_DEFS += YYDEBUG
+- VBoxDTraceCmd_DEFS.linux = _XOPEN_SOURCE=700
++ VBoxDTraceCmd_DEFS.linux = _XOPEN_SOURCE=700 _DEFAULT_SOURCE
+  VBoxDTraceCmd_DEFS.win = YY_USE_PROTOS=1 YYENABLE_NLS=0 YYLTYPE_IS_TRIVIAL=0
+  VBoxDTraceCmd_SDKS = VBOX_ZLIB
+  ifn1of ($(KBUILD_TARGET), win)
diff --git a/virtualbox.changes b/virtualbox.changes
index a7636f4..028d878 100644
--- a/virtualbox.changes
+++ b/virtualbox.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Mon Aug  7 10:24:42 UTC 2017 - schwab@suse.de
+
+- internal-headers.patch: fix invalid use of internal headers, enable
+  POSIX extensions
+
 -------------------------------------------------------------------
 Thu Aug  3 17:37:58 UTC 2017 - hpj@urpla.net
 
diff --git a/virtualbox.spec b/virtualbox.spec
index 2648eb0..808151e 100644
--- a/virtualbox.spec
+++ b/virtualbox.spec
@@ -105,6 +105,8 @@ Patch115:       vbox_fix_for_gcc7.patch
 Patch116:       Fix_for_server_1.19.patch
 # Fix for missing cleanup in KMS support
 Patch117:       fix_KMS_support.patch
+# Fix invalid use of internal headers
+Patch118:       internal-headers.patch
 #
 BuildRequires:  LibVNCServer-devel
 BuildRequires:  SDL-devel
@@ -386,6 +388,7 @@ as an "extpack" for VirtualBox. The implementation is licensed under GPL.
 %patch115 -p1
 %patch116 -p1
 %patch117 -p1
+%patch118 -p1
 
 #copy user manual
 cp %{SOURCE1} UserManual.pdf