diff --git a/build.sh b/build.sh
index 7a8e95ee7..6c6150e8f 100755
--- a/build.sh
+++ b/build.sh
@@ -591,8 +591,6 @@ qmake_options=(
   -recursive
   CONFIG+="$CONFIG"
   RUBYLIBFILE="$RUBYLIBFILE"
-  RUBYINCLUDE="$RUBYINCLUDE"
-  RUBYINCLUDE2="$RUBYINCLUDE2"
   RUBYVERSIONCODE="$RUBYVERSIONCODE"
   HAVE_RUBY="$HAVE_RUBY"
   PYTHON="$PYTHON"
@@ -613,6 +611,16 @@ qmake_options=(
   KLAYOUT_VERSION_REV="$KLAYOUT_VERSION_REV"
 )
 
+# NOTE: qmake does not like include paths which clash with paths built into the compiler
+# hence we don't add RUBYINCLUDE or RUBYINCLUDE2 in this case (found on CentOS 8 where Ruby
+# headers are installed in /usr/include)
+if [ "$RUBYINCLUDE" != "/usr/include" ] && [  "$RUBYINCLUDE" != "/usr/local/include" ]; then
+  qmake_options+=( RUBYINCLUDE="$RUBYINCLUDE" )
+fi
+if [ "$RUBYINCLUDE2" != "/usr/include" ] && [  "$RUBYINCLUDE2" != "/usr/local/include" ]; then
+  qmake_options+=( RUBYINCLUDE2="$RUBYINCLUDE2" )
+fi
+
 # This should speed up build time considerably
 # https://ortogonal.github.io/ccache-and-qmake-qtcreator/
 if [ "$QMAKE_CCACHE" = 1 ]; then
diff --git a/scripts/rpm-data/klayout.spec b/scripts/rpm-data/klayout.spec
index 4cd9b3216..e326ed4ff 100644
--- a/scripts/rpm-data/klayout.spec
+++ b/scripts/rpm-data/klayout.spec
@@ -31,6 +31,24 @@ Source0:        http://www.klayout.de/downloads/%{name}-%{version}.tar.gz
 # so's of klayout itself)
 AutoReqProv: 	no
 
+# CentOS8 requirements
+%if "%{target_system}" == "centos8"
+Requires:	ruby >= 2.5.5
+Requires:	python3 >= 3.6.0
+Requires: qt5-qtbase >= 5.11.1
+Requires: qt5-qtmultimedia >= 5.11.1
+Requires: qt5-qtxmlpatterns >= 5.11.1
+Requires: qt5-qtsvg >= 5.11.1
+Requires: qt5-qttools >= 5.11.1
+# NOTE: this package is required for libQt5Designer and pulls in a lot of devel stuff.
+# Maybe it's worth considering to drop designer support and replace by QUiLoader.
+Requires: qt5-qttools-devel >= 5.11.1
+
+%define buildopt -j2
+%define pylib %{python_sitearch}
+%define __python /usr/bin/python3
+%endif
+
 # CentOS7 requirements
 %if "%{target_system}" == "centos7"
 Requires:	ruby >= 2.0.0
diff --git a/testdata/ruby/qtbinding.rb b/testdata/ruby/qtbinding.rb
index 6a9eb9531..b526f3a53 100644
--- a/testdata/ruby/qtbinding.rb
+++ b/testdata/ruby/qtbinding.rb
@@ -623,7 +623,7 @@ class QtBinding_TestClass < TestBase
     w.setLayout(l)
 
     w._destroy
-    assert_equal(l.destroyed?, true)
+    assert_equal(l._destroyed?, true)
 
   end
 
@@ -637,7 +637,7 @@ class QtBinding_TestClass < TestBase
     wc.setParent(w)
 
     w._destroy
-    assert_equal(wc.destroyed?, true)
+    assert_equal(wc._destroyed?, true)
 
   end
 
@@ -651,7 +651,7 @@ class QtBinding_TestClass < TestBase
     wc.setParent(w)
 
     w._destroy
-    assert_equal(wc.destroyed?, true)
+    assert_equal(wc._destroyed?, true)
 
   end
 
@@ -667,9 +667,9 @@ class QtBinding_TestClass < TestBase
     wc.setParent(nil)
 
     w._destroy
-    assert_equal(wc.destroyed?, false)
+    assert_equal(wc._destroyed?, false)
     wc._destroy
-    assert_equal(wc.destroyed?, true)
+    assert_equal(wc._destroyed?, true)
 
   end