diff --git a/configure.ac b/configure.ac
index f5e633ae8..cec8c949e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,7 +13,7 @@ PKG_PROG_PKG_CONFIG
 
 # Checks for programs.
 AC_CHECK_PROG(PERL, perl, perl)
-AC_CHECK_PROG(MOC, moc, moc)
+AC_PATH_PROG(MOC, [moc-qt4 moc], moc)
 AC_PROG_CXX
 AC_PROG_AWK
 AC_PROG_CC_C99
diff --git a/lib/upipe-qt/Makefile.am b/lib/upipe-qt/Makefile.am
index 2a5cf095d..9651ef45b 100644
--- a/lib/upipe-qt/Makefile.am
+++ b/lib/upipe-qt/Makefile.am
@@ -2,6 +2,8 @@ if HAVE_QTWEBKIT
 lib_LTLIBRARIES = libupipe_qt.la
 endif
 
+BUILT_SOURCES = moc_thumbnail.cpp
+CLEANFILES = moc_thumbnail.cpp
 
 moc_thumbnail.cpp: thumbnail.h 
 	$(MOC) -DQT_NO_DEBUG -DQT_WEBKIT_LIB -DQT_GUI_LIB -DQT_CORE_LIB $(QTWEBKIT_CFLAGS) -I. $< -o $@