diff --git a/configure.ac b/configure.ac
index 62e0c03..3e17121 100644
--- a/configure.ac
+++ b/configure.ac
@@ -77,7 +77,7 @@ AM_CONDITIONAL(USE_SDL, test "${ac_cv_my_have_sdl}" = "yes")
 # Use OpenCV?
 ac_cv_my_have_opencv="no"
 OPENCV="no"
-PKG_CHECK_MODULES(OPENCV, opencv, [ac_cv_my_have_opencv="yes"])
+PKG_CHECK_MODULES(OPENCV, opencv, [ac_cv_my_have_opencv="yes"], [:])
 if test "${ac_cv_my_have_opencv}" != "no"; then
   AC_DEFINE(USE_OPENCV, 1, Define to 1 to use OpenCV)
 fi
@@ -86,7 +86,7 @@ AM_CONDITIONAL(USE_OPENCV, test "${ac_cv_my_have_opencv}" = "yes")
 # Use Imlib2?
 ac_cv_my_have_imlib2="no"
 IMLIB2="no"
-PKG_CHECK_MODULES(IMLIB2, imlib2, [ac_cv_my_have_imlib2="yes"])
+PKG_CHECK_MODULES(IMLIB2, imlib2, [ac_cv_my_have_imlib2="yes"], [:])
 if test "${ac_cv_my_have_imlib2}" != "no"; then
   AC_DEFINE(USE_IMLIB2, 1, Define to 1 to use Imlib2)
 fi