diff --git a/externals/Makefile b/externals/Makefile
index e60a73c9..09066109 100644
--- a/externals/Makefile
+++ b/externals/Makefile
@@ -658,6 +658,10 @@ $(gem_src)/Gem.pd_linux: $(gem_src)/configure
 	test -s $(gem_src)/Gem.pd_linux || \
 		cd $(gem_src) && ./configure \
 			CXXFLAGS="-DHAVE_S_STUFF_H" \
+			PKG_IMAGEMAGICK___CFLAGS="$(shell pkg-config --cflags ImageMagick-6.Q16HDRI)" \
+			PKG_IMAGEMAGICK___LIBS="$(shell pkg-config --libs ImageMagick-6.Q16HDRI)" \
+			PKG_MAGICKCORE_CFLAGS="$(shell pkg-config --cflags MagickCore-6.Q16HDRI)" \
+			PKG_MAGICKCORE_LIBS="$(shell pkg-config --libs MagickCore-6.Q16HDRI)" \
 			--prefix=$(prefix) \
 			--with-video=plugins \
 			--with-film=plugins \