diff --git a/libqt5-qtdoc.changes b/libqt5-qtdoc.changes
index e04a2f5..4a259e0 100644
--- a/libqt5-qtdoc.changes
+++ b/libqt5-qtdoc.changes
@@ -1,3 +1,15 @@
+-------------------------------------------------------------------
+Fri Jun  8 09:23:43 UTC 2018 - fabian@ritter-vogt.de
+
+- Add patch to fix building on 32-bit architectures (boo#1092425):
+  * workaround-qdoc-failure.patch
+
+-------------------------------------------------------------------
+Sun Jun  3 10:47:04 UTC 2018 - wbauer@tmo.at
+
+- BuildRequire clang, this is needed since 5.11 to properly build
+  the docs
+
 -------------------------------------------------------------------
 Tue May 22 16:01:37 CEST 2018 - fabian@ritter-vogt.de
 
diff --git a/libqt5-qtdoc.spec b/libqt5-qtdoc.spec
index fefc5bc..a1929e3 100644
--- a/libqt5-qtdoc.spec
+++ b/libqt5-qtdoc.spec
@@ -27,7 +27,10 @@ License:        LGPL-2.1-with-Qt-Company-Qt-exception-1.1 or LGPL-3.0-only
 Group:          Documentation/Other
 URL:            https://www.qt.io
 Source:         https://download.qt.io/official_releases/qt/5.11/%{real_version}/single/%{tar_version}.tar.xz
+# PATCH-FIX-OPENSUSE
+Patch100:       workaround-qdoc-failure.patch
 BuildRequires:  alsa-devel
+BuildRequires:  clang
 BuildRequires:  cups-devel
 BuildRequires:  double-conversion-devel
 BuildRequires:  gcc-c++
@@ -115,6 +118,7 @@ required.
 
 %prep
 %setup -q -n %{tar_version}
+%autopatch -p1
 
 %build
 # We need to link to some of the programs used as that the source assumes they were just build.
diff --git a/workaround-qdoc-failure.patch b/workaround-qdoc-failure.patch
new file mode 100644
index 0000000..687551f
--- /dev/null
+++ b/workaround-qdoc-failure.patch
@@ -0,0 +1,30 @@
+From: Michal Srb <msrb@suse.com>
+Subject: Assertion failure in libclang on i586 (when building qtdoc)
+References: boo#1092425
+
+I have found that the issue is caused by `qfloat::operator float()` in qtbase/src/corelib/global/qfloat16.h.
+
+For some reason the declaration is omitted when building the documentation using `#ifndef Q_QDOC`, but its definition is there unconditionally. Omitting the definition prevents the qdoc failure. See the attached patch.
+
+I don't know yet why it behaves differently on x86 and x86_64, perhaps it has something to do with the body of the method, which is different depending on the architecture.
+
+Also, even with broken code, it should not crash with assertion failure. So there must be something broken in either libclang or qdoc, but I did not yet find what. Perhaps we could use this patch for the time being.
+
+--- qt-everywhere-src-5.11.0-rc.out/qtbase/src/corelib/global/qfloat16.h	2018-05-30 08:12:03.405142221 +0000
++++ qt-everywhere-src-5.11.0-rc/qtbase/src/corelib/global/qfloat16.h	2018-05-30 07:59:19.637190880 +0000
+@@ -144,6 +144,7 @@
+ }
+ QT_WARNING_POP
+ 
++#ifndef Q_QDOC
+ inline qfloat16::operator float() const Q_DECL_NOTHROW
+ {
+ #if defined(QT_COMPILER_SUPPORTS_F16C) && defined(__F16C__)
+@@ -162,6 +163,7 @@
+     return f;
+ #endif
+ }
++#endif
+ 
+ inline qfloat16 operator-(qfloat16 a) Q_DECL_NOTHROW
+ {