on OSX, 'make uninstall' should clean files under /usr/local rather than /usr
diff --git a/make.sh b/make.sh
index 622d6a9..d4fa43f 100755
--- a/make.sh
+++ b/make.sh
@@ -82,6 +82,7 @@
 	if [ "$(uname)" == "Darwin" ]; then
 		# find the directory automatically, so we can support both Macport & Brew
 		PKGCFGDIR="$(pkg-config --variable pc_path pkg-config | cut -d ':' -f 1)"
+		export PREFIX=/usr/local
 		if [ ${PKGCFGDIR}x != x ]; then
 			${MAKE} PKGCFGDIR=$PKGCFGDIR uninstall
 		else