diff --git a/scripts/config-printflags.sh b/scripts/config-printflags.sh
index 05ddee5..55b0345 100755
--- a/scripts/config-printflags.sh
+++ b/scripts/config-printflags.sh
@@ -2,7 +2,7 @@
 
 for pkg in $@
 do
-	varname="$(echo "${pkg}" | tr a-z A-Z)"
+	varname="$(echo "${pkg}" | tr 'a-z-+' 'A-Z__')"
 	echo '[ -z "${'${varname}'_CFLAGS}" ] && '${varname}'_CFLAGS="$('${pkg}'-config --cflags)"'
 	echo '[ -z "${'${varname}'_LIBS}" ] && '${varname}'_LIBS="$('${pkg}'-config --libs)"'
 done