diff --git a/MozillaThunderbird.changes b/MozillaThunderbird.changes
index e4a8a13..88c8a35 100644
--- a/MozillaThunderbird.changes
+++ b/MozillaThunderbird.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Mon Jan 18 07:32:51 UTC 2016 - olaf@aepfle.de
+
+- Add build conditionals for valgrind and -Os
+- Convert existing conditions for kde to bcond
+
 -------------------------------------------------------------------
 Tue Dec 29 20:30:59 UTC 2015 - wr@rosenauer.org
 
diff --git a/MozillaThunderbird.spec b/MozillaThunderbird.spec
index d393b96..d460769 100644
--- a/MozillaThunderbird.spec
+++ b/MozillaThunderbird.spec
@@ -1,7 +1,7 @@
 #
 # spec file for package MozillaThunderbird
 #
-# Copyright (c) 2015 SUSE LINUX GmbH, Nuernberg, Germany.
+# Copyright (c) 2016 SUSE LINUX GmbH, Nuernberg, Germany.
 #               2006-2015 Wolfgang Rosenauer <wr@rosenauer.org>
 #
 # All modifications and additions to the file contributed by third parties
@@ -29,7 +29,9 @@
 %endif
 %endif
 
-%define with_kde 1
+%bcond_without mozilla_tb_kde4
+%bcond_with    mozilla_tb_valgrind
+%bcond_without mozilla_tb_optimize_for_size
 
 Name:           MozillaThunderbird
 BuildRequires:  Mesa-devel
@@ -54,6 +56,9 @@ BuildRequires:  xz
 BuildRequires:  yasm
 BuildRequires:  zip
 BuildRequires:  pkgconfig(libpulse)
+%if %{with mozilla_tb_valgrind}
+BuildRequires:  pkgconfig(valgrind)
+%endif
 %if %suse_version > 1210
 BuildRequires:  pkgconfig(gstreamer-%gstreamer_ver)
 BuildRequires:  pkgconfig(gstreamer-app-%gstreamer_ver)
@@ -74,7 +79,7 @@ Release:        0
 Provides:       thunderbird = %{version}
 Provides:       appdata()
 Provides:       appdata(thunderbird.appdata.xml)
-%if %{with_kde}
+%if %{with mozilla_tb_kde4}
 # this is needed to match this package with the kde4 helper package without the main package
 # having a hard requirement on the kde4 package
 %define kde_helper_version 6
@@ -194,7 +199,7 @@ symbols meant for upload to Mozilla's crash collector database.
 pushd mozilla
 %patch1 -p1
 %patch2 -p1
-%if %{with_kde}
+%if %{with mozilla_tb_kde4}
 %patch3 -p1
 %endif
 %patch4 -p1
@@ -212,7 +217,7 @@ DATE="\"$(date -d "${modified}" "+%%b %%e %%Y")\""
 TIME="\"$(date -d "${modified}" "+%%R")\""
 find . -regex ".*\.c\|.*\.cpp\|.*\.h" -exec sed -i "s/__DATE__/${DATE}/g;s/__TIME__/${TIME}/g" {} +
 #
-%if %{with_kde}
+%if %{with mozilla_tb_kde4}
 kdehelperversion=$(cat mozilla/toolkit/xre/nsKDEUtils.cpp | grep '#define KMOZILLAHELPER_VERSION' | cut -d ' ' -f 3)
 if test "$kdehelperversion" != %{kde_helper_version}; then
   echo fix kde helper version in the .spec file
@@ -226,7 +231,10 @@ export BUILD_OFFICIAL=1
 %if %{update_channel} == "esr"
 export MOZ_ESR=1
 %endif
-export CFLAGS="$RPM_OPT_FLAGS -Os -fno-strict-aliasing"
+export CFLAGS="$RPM_OPT_FLAGS -fno-strict-aliasing"
+%if %{with mozilla_tb_optimize_for_size}
+export CFLAGS="$CFLAGS -Os"
+%endif
 %ifarch ppc64 ppc64le
 export CFLAGS="$CFLAGS -mminimal-toc"
 %endif
@@ -281,6 +289,10 @@ ac_add_options --disable-crashreporter
 %ifarch %arm
 ac_add_options --disable-neon
 %endif
+%if %{with mozilla_tb_valgrind}
+ac_add_options --disable-jemalloc
+ac_add_options --enable-valgrind
+%endif
 EOF
 make -f client.mk build
 
@@ -291,7 +303,7 @@ make -C mail/installer STRIP=/bin/true MOZ_PKG_FATAL_WARNINGS=0
 mkdir -p $RPM_BUILD_ROOT%{progdir}
 cp -rf $RPM_BUILD_DIR/obj/dist/thunderbird/* \
        $RPM_BUILD_ROOT%{progdir}
-%if %{with_kde}
+%if %{with mozilla_tb_kde4}
 # install kde.js
 install -m 644 %{SOURCE12} $RPM_BUILD_ROOT%{progdir}/defaults/pref/kde.js
 # make sure that instantApply is true by default