diff --git a/perl/perl-tk/patches/804.029-X11_XLIB_H.patch b/perl/perl-tk/patches/804.029-X11_XLIB_H.patch
new file mode 100644
index 0000000000..7a43a7ade8
--- /dev/null
+++ b/perl/perl-tk/patches/804.029-X11_XLIB_H.patch
@@ -0,0 +1,19 @@
+https://bugs.gentoo.org/show_bug.cgi?id=345987
+--- Tk-804.029/pTk/Xlib.h
++++ Tk-804.029/pTk/Xlib.h
+@@ -1,6 +1,7 @@
+ #ifndef _XLIB
+ #define _XLIB
+ #ifndef _XLIB_H_
++#ifndef _X11_XLIB_H_
+ extern XFontStruct *XLoadQueryFont  _ANSI_ARGS_((Display *, const char *));
+ extern XModifierKeymap *XGetModifierMapping  _ANSI_ARGS_((Display *));
+ extern XImage *XCreateImage  _ANSI_ARGS_((Display *, Visual *, unsigned int, int, int, char *, unsigned int, unsigned int, int, int));
+@@ -143,6 +144,7 @@
+ extern Window XGetSelectionOwner _ANSI_ARGS_((Display *, Atom));
+ extern int XRectInRegion _ANSI_ARGS_((Region,int,int,unsigned,unsigned));
+ extern int XSubtractRegion _ANSI_ARGS_((Region, Region, Region));
++#endif /* _X11_XLIB_H_ */
+ #endif /* _XLIB_H_ */
+ extern int _XInitImageFuncPtrs _ANSI_ARGS_((XImage *image));
+ #endif /* _XLIB */
diff --git a/perl/perl-tk/perl-tk-804.029.diff b/perl/perl-tk/patches/perl-tk-804.029.diff
similarity index 100%
rename from perl/perl-tk/perl-tk-804.029.diff
rename to perl/perl-tk/patches/perl-tk-804.029.diff
diff --git a/perl/perl-tk/perl-tk.SlackBuild b/perl/perl-tk/perl-tk.SlackBuild
index 11b9d93e12..9082204c46 100644
--- a/perl/perl-tk/perl-tk.SlackBuild
+++ b/perl/perl-tk/perl-tk.SlackBuild
@@ -6,7 +6,7 @@
 
 PRGNAM=perl-tk
 VERSION=${VERSION:-804.029}
-BUILD=${BUILD:-1}
+BUILD=${BUILD:-2}
 TAG=${TAG:-_SBo}
 
 if [ -z "$ARCH" ]; then
@@ -52,7 +52,11 @@ find . \
  -exec chmod 644 {} \;
 
 # Apply a few patches
-patch -p1 < $CWD/$PRGNAM-$VERSION.diff
+patch -p1 < $CWD/patches/$PRGNAM-$VERSION.diff
+
+#  Fix build failure with libX11-1.4.0 where they added an "X11_" string to
+#  header guards to avoid possible collision.
+patch -p1 < $CWD/patches/804.029-X11_XLIB_H.patch
 
 # XFT=1 (font manager) support, which gives perl-tk programs the ability to
 # use all fonts accessible from XFT and antialiasing.