diff --git a/hw/kdrive/ephyr/XF86dri.c b/hw/kdrive/ephyr/XF86dri.c
index e656ff5a0..63e630c9c 100644
--- a/hw/kdrive/ephyr/XF86dri.c
+++ b/hw/kdrive/ephyr/XF86dri.c
@@ -45,6 +45,16 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #ifdef HAVE_CONFIG_H
 #include <kdrive-config.h>
 #endif
+/*
+ * including some server headers (like kdrive-config.h)
+ * might define the macro _XSERVER64
+ * on 64 bits machines. That macro must _NOT_ be defined for Xlib
+ * client code, otherwise bad things happen.
+ * So let's undef that macro if necessary.
+ */
+#ifdef _XSERVER64
+#undef _XSERVER64
+#endif
 
 #ifdef XEPHYR_DRI
 
diff --git a/hw/kdrive/ephyr/ephyrhostglx.c b/hw/kdrive/ephyr/ephyrhostglx.c
index f5db5be16..1eec4e02b 100644
--- a/hw/kdrive/ephyr/ephyrhostglx.c
+++ b/hw/kdrive/ephyr/ephyrhostglx.c
@@ -31,6 +31,17 @@
 #include <kdrive-config.h>
 #endif
 
+/*
+ * including some server headers (like kdrive-config.h)
+ * might define the macro _XSERVER64
+ * on 64 bits machines. That macro must _NOT_ be defined for Xlib
+ * client code, otherwise bad things happen.
+ * So let's undef that macro if necessary.
+ */
+#ifdef _XSERVER64
+#undef _XSERVER64
+#endif
+
 #include <X11/Xlibint.h>
 #include <GL/glx.h>
 #include <GL/internal/glcore.h>
diff --git a/hw/kdrive/ephyr/ephyrhostvideo.c b/hw/kdrive/ephyr/ephyrhostvideo.c
index 562c2a4e8..41c0b755b 100644
--- a/hw/kdrive/ephyr/ephyrhostvideo.c
+++ b/hw/kdrive/ephyr/ephyrhostvideo.c
@@ -28,6 +28,16 @@
 #ifdef HAVE_CONFIG_H
 #include <kdrive-config.h>
 #endif
+/*
+ * including some server headers (like kdrive-config.h)
+ * might define the macro _XSERVER64
+ * on 64 bits machines. That macro must _NOT_ be defined for Xlib
+ * client code, otherwise bad things happen.
+ * So let's undef that macro if necessary.
+ */
+#ifdef _XSERVER64
+#undef _XSERVER64
+#endif
 #include <X11/Xutil.h>
 #include <X11/Xlibint.h>
 #include <X11/extensions/Xvlib.h>
diff --git a/hw/kdrive/ephyr/hostx.c b/hw/kdrive/ephyr/hostx.c
index 1a71d0641..c870a291d 100644
--- a/hw/kdrive/ephyr/hostx.c
+++ b/hw/kdrive/ephyr/hostx.c
@@ -27,6 +27,18 @@
 #include <kdrive-config.h>
 #endif
 
+/*
+ * including some server headers (like kdrive-config.h)
+ * might define the macro _XSERVER64
+ * on 64 bits machines. That macro must _NOT_ be defined for Xlib
+ * client code, otherwise bad things happen.
+ * So let's undef that macro if necessary.
+ */
+#ifdef _XSERVER64
+#undef _XSERVER64
+#endif
+
+
 #include "hostx.h"
 
 #include <stdlib.h>