diff --git a/.gitignore b/.gitignore
index 6a0fd60..5f669b5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@
 /qtbase-everywhere-src-5.15.1.tar.xz
 /qtbase-everywhere-src-5.15.2.tar.xz
 /kde-5.15-rollup-20210907.patch.gz
+/kde-5.15-rollup-20211012.patch.gz
diff --git a/qt5-qtbase.spec b/qt5-qtbase.spec
index d5a9849..9521b04 100644
--- a/qt5-qtbase.spec
+++ b/qt5-qtbase.spec
@@ -57,7 +57,7 @@ BuildRequires: pkgconfig(libsystemd)
 Name:    qt5-qtbase
 Summary: Qt5 - QtBase components
 Version: 5.15.2
-Release: 26%{?dist}
+Release: 27%{?dist}
 
 
 # See LGPL_EXCEPTIONS.txt, for exception details
@@ -114,6 +114,9 @@ Patch54: qtbase-qmake_LFLAGS.patch
 # don't use relocatable heuristics to guess prefix when using -no-feature-relocatable
 Patch55: qtbase-everywhere-src-5.14.2-no_relocatable.patch
 
+# fix FTBFS against libglvnd-1.3.4+
+Patch56: qtbase-everywhere-src-5.15.2-libglvnd.patch
+
 # drop -O3 and make -O2 by default
 Patch61: qt5-qtbase-cxxflag.patch
 
@@ -140,7 +143,7 @@ Patch90: %{name}-gcc11.patch
 # https://invent.kde.org/qt/qt/qtbase, kde/5.15 branch
 # git diff v5.15.2..HEAD | gzip > kde-5.15-rollup-$(date +%Y%m%d).patch.gz
 # patch100 in lookaside cache due to large'ish size -- rdieter
-Patch100: kde-5.15-rollup-20210907.patch.gz
+Patch100: kde-5.15-rollup-20211012.patch.gz
 Patch101: 0068-Bump-version.patch
 
 Patch102: qtbase-CVE-2021-38593.patch
@@ -398,6 +401,7 @@ Qt5 libraries used for drawing widgets and OpenGL items.
 %patch53 -p1 -b .qt5gui_cmake_isystem_includes
 %patch54 -p1 -b .qmake_LFLAGS
 %patch55 -p1 -b .no_relocatable
+%patch56 -p1 -b .libglvnd
 %patch61 -p1 -b .qt5-qtbase-cxxflag
 %if 0%{?fedora} < 35
 %patch63 -p1 -b .firebird
@@ -494,7 +498,7 @@ export MAKEFLAGS="%{?_smp_mflags}"
   -shared \
   -accessibility \
   %{?dbus}%{!?dbus:-dbus-runtime} \
-  %{?egl:-egl} \
+  %{?egl:-egl -eglfs} \
   -fontconfig \
   -glib \
   -gtk \
@@ -530,6 +534,16 @@ export MAKEFLAGS="%{?_smp_mflags}"
   QMAKE_CXXFLAGS_RELEASE="${CXXFLAGS:-$RPM_OPT_FLAGS}" \
   QMAKE_LFLAGS_RELEASE="${LDFLAGS:-$RPM_LD_FLAGS}"
 
+# Validate config results
+for config_test in egl-x11 ; do
+config_result="$(grep ^cache.${config_test}.result config.cache | cut -d= -f2 | tr -d ' ')"
+if [ "${config_result}" != "true" ]; then
+  echo "${config_test} detection failed"
+  config_failed=1
+fi
+done
+if [ ${config_failed} -eq 1 ]; then exit 1; fi
+
 # ensure qmake build using optflags (which can happen if not munging qmake.conf defaults)
 make clean -C qmake
 %make_build -C qmake all binary \
@@ -1102,6 +1116,13 @@ fi
 
 
 %changelog
+* Mon Oct 18 2021 Jan Grulich <jgrulich@redhat.com> - 5.15.2-27
+- Sync with Fedora:
+  - sync kde/5.15 branch patches
+  - validate configure results (base, egl-x11)
+
+  Resolves: bz#2014991
+
 * Wed Sep 08 2021 Jan Grulich <jgrulich@redhat.com> - 5.15.2-26
 - Sync with Fedora:
   - sync kde/5.15 branch patches
diff --git a/qtbase-everywhere-src-5.15.2-libglvnd.patch b/qtbase-everywhere-src-5.15.2-libglvnd.patch
new file mode 100644
index 0000000..e819f8d
--- /dev/null
+++ b/qtbase-everywhere-src-5.15.2-libglvnd.patch
@@ -0,0 +1,15 @@
+diff -up qtbase-everywhere-src-5.15.2/src/gui/configure.json.libglvnd qtbase-everywhere-src-5.15.2/src/gui/configure.json
+--- qtbase-everywhere-src-5.15.2/src/gui/configure.json.libglvnd	2020-10-27 03:02:11.000000000 -0500
++++ qtbase-everywhere-src-5.15.2/src/gui/configure.json	2021-09-10 10:05:53.610312223 -0500
+@@ -847,9 +847,9 @@
+                 ],
+                 "include": [ "EGL/egl.h", "X11/Xlib.h" ],
+                 "main": [
+-                    "Display *dpy = EGL_DEFAULT_DISPLAY;",
++                    "Display *dpy = reinterpret_cast<Display *>(EGL_DEFAULT_DISPLAY);",
+                     "EGLNativeDisplayType egldpy = XOpenDisplay(\"\");",
+-                    "dpy = egldpy;",
++                    "dpy = reinterpret_cast<Display *>(egldpy);",
+                     "EGLNativeWindowType w = XCreateWindow(dpy, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);",
+                     "XDestroyWindow(dpy, w);",
+                     "XCloseDisplay(dpy);"
diff --git a/sources b/sources
index 98f0df5..def06fa 100644
--- a/sources
+++ b/sources
@@ -1,2 +1,2 @@
 SHA512 (qtbase-everywhere-src-5.15.2.tar.xz) = a549bfaf867d746ff744ab224eb65ac1bdcdac7e8457dfa379941b2b225a90442fcfc1e1175b9afb1f169468f8130b7ab917c67be67156520a4bfb5c92d304f9
-SHA512 (kde-5.15-rollup-20210907.patch.gz) = 34775f02eb4ae8a41f919fe2eb69ba6978235d6fbab412b403147f38ee609a06d1936adfe494e011a078e912e309093cdede0598b0151ac5bbc095da3fdfeff1
+SHA512 (kde-5.15-rollup-20211012.patch.gz) = e265b53b179c68f6ada3f05126b067003f4c6a7e0d7262dac6e6a2c4fcbae9f554b3d69c987c7173c45cbbcc79810c169ae038906418a8b6ad0009a69660e0f9