Fix silly gcc10 thing

0001-xt-Work-around-a-compiler-issue-with-gcc-10.patch

@@ -0,0 +1,100 @@
+From f3079e509c5cf60042ae2261499ee13b6b02498a Mon Sep 17 00:00:00 2001
+From: Adam Jackson <ajax@redhat.com>
+Date: Thu, 6 Feb 2020 13:45:35 -0500
+Subject: [PATCH] xt: Work around a compiler issue with gcc 10
+
+GRABEXT() is used to look up a pointer that sometimes lives just past
+the end of an XtServerGrabRec. Whether it's really there or not depends
+on XtServerGrabRec::hasExt. In a couple of places, we build those
+structs on the stack and pass them to other functions; such structs
+always have hasExt == 0, so GRABEXT would never get called in practice.
+However, there exists a bug in gcc 10 - more or less difficult to hit,
+depending on your compiler options and architecture - where it would not
+notice that the dereference after GRABEXT is dead code, at which point
+it looks like you're dereferencing one past the end of the array, which
+is illegal, and you you get:
+
+    PassivGrab.c:292:35: error: array subscript 0 is outside array bounds
+    of 'XtServerGrabRec[1]' {aka 'struct _XtServerGrabRec[1]'}
+    [-Werror=array-bounds]
+
+As a completely stupid workaround, build those on-stack structs as
+arrays of two, so that the (dead) dereference looks like it's pointing
+into the dummy member of the array. This is almost certainly a compiler
+bug and I don't encourage merging this patch upstream, but if you need
+to build libXt with gcc 10 absolutely right this second, here it is.
+
+For details on the gcc issue, see:
+
+https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93582
+---
+ src/PassivGrab.c | 24 ++++++++++++------------
+ 1 file changed, 12 insertions(+), 12 deletions(-)
+
+diff --git a/src/PassivGrab.c b/src/PassivGrab.c
+index bece0d9..b174d40 100644
+--- a/src/PassivGrab.c
++++ b/src/PassivGrab.c
+@@ -553,7 +553,7 @@ XtServerGrabPtr _XtCheckServerGrabsOnWidget (
+     _XtBoolean		isKeyboard)
+ {
+     register XtServerGrabPtr grab;
+-    XtServerGrabRec 	tempGrab;
++    XtServerGrabRec 	tempGrab[2];
+     XtServerGrabPtr	*passiveListPtr;
+     XtPerWidgetInput	pwi;
+ 
+@@ -577,13 +577,13 @@ XtServerGrabPtr _XtCheckServerGrabsOnWidget (
+     /* Take only the lower thirteen bits as modifier state.  The X Keyboard
+      * Extension may be representing keyboard group state in two upper bits.
+      */
+-    tempGrab.widget = widget;
+-    tempGrab.keybut = (KeyCode) event->xkey.keycode; /* also xbutton.button */
+-    tempGrab.modifiers = event->xkey.state & 0x1FFF; /*also xbutton.state*/
+-    tempGrab.hasExt = False;
++    tempGrab[0].widget = widget;
++    tempGrab[0].keybut = (KeyCode) event->xkey.keycode; /* also xbutton.button */
++    tempGrab[0].modifiers = event->xkey.state & 0x1FFF; /*also xbutton.state*/
++    tempGrab[0].hasExt = False;
+ 
+     for (grab = *passiveListPtr; grab; grab = grab->next) {
+-	if (GrabMatchesSecond(&tempGrab, grab))
++	if (GrabMatchesSecond(tempGrab, grab))
+ 	    return (grab);
+     }
+     return (XtServerGrabPtr)NULL;
+@@ -775,17 +775,17 @@ void   UngrabKeyOrButton (
+     Modifiers	modifiers,
+     Boolean	isKeyboard)
+ {
+-    XtServerGrabRec 	tempGrab;
++    XtServerGrabRec 	tempGrab[2];
+     XtPerWidgetInput	pwi;
+ 
+     XtCheckSubclass(widget, coreWidgetClass,
+ 		    "in XtUngrabKey or XtUngrabButton");
+ 
+     /* Build a temporary grab list entry */
+-    tempGrab.widget = widget;
+-    tempGrab.modifiers = (unsigned short) modifiers;
+-    tempGrab.keybut = (KeyCode) keyOrButton;
+-    tempGrab.hasExt = False;
++    tempGrab[0].widget = widget;
++    tempGrab[0].modifiers = (unsigned short) modifiers;
++    tempGrab[0].keybut = (KeyCode) keyOrButton;
++    tempGrab[0].hasExt = False;
+ 
+     LOCK_PROCESS;
+     pwi = _XtGetPerWidgetInput(widget, FALSE);
+@@ -817,7 +817,7 @@ void   UngrabKeyOrButton (
+ 
+     /* Delete all entries which are encompassed by the specified grab. */
+     DeleteServerGrabFromList(isKeyboard ? &pwi->keyList : &pwi->ptrList,
+-			     &tempGrab);
++			     tempGrab);
+ }
+ 
+ void  XtGrabKey (
+-- 
+2.23.0
+

libXt.spec

@@ -7,16 +7,18 @@ Name: libXt
 Version: 1.2.0
 Release: 1%{?gitdate:.%{gitdate}git%{gitversion}}%{?dist}
 License: MIT
-URL: http://www.x.org
+URL: https://www.x.org
 
 %if 0%{?gitdate}
 Source0:    %{tarball}-%{gitdate}.tar.bz2
 Source1:    make-git-snapshot.sh
 Source2:    commitid
 %else
-Source0: http://xorg.freedesktop.org/archive/individual/lib/%{name}-%{version}.tar.bz2
+Source0: https://xorg.freedesktop.org/archive/individual/lib/%{name}-%{version}.tar.bz2
 %endif
 
+Patch0: 0001-xt-Work-around-a-compiler-issue-with-gcc-10.patch
+
 Requires: libX11%{?_isa} >= 1.6
 
 BuildRequires: xorg-x11-util-macros
@@ -109,6 +111,7 @@ cp -p COPYING ${RPM_BUILD_ROOT}%{_datadir}/doc/%{name}/COPYING
 %changelog
 * Thu Feb 06 2020 Adam Jackson <ajax@redhat.com> - 1.2.0-1
 - libXt 1.2.0
+- Work around a gcc10 issue
 
 * Wed Jan 29 2020 Fedora Release Engineering <releng@fedoraproject.org> - 1.1.5-13.20190424gitba4ec9376
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_32_Mass_Rebuild