diff --git a/build/mkdeps.sh b/build/mkdeps.sh
index ffee0bd..b0f06d3 100755
--- a/build/mkdeps.sh
+++ b/build/mkdeps.sh
@@ -14,7 +14,7 @@
 #
 files=`ls $1/*.F90`
 for src in $files; do
-  deps=`awk '/^\s*[Uu][Ss][Ee] / {gsub ( "[:,]","" ) ; print $2}' $src | sort | uniq`
+  deps=`awk '/^\s*[Uu][Ss][Ee] / {gsub ( "[:,]","" ) ; print tolower($2)}' $src | sort | uniq`
   fname=`basename $src .F90`
   output="$2/${fname}.o: $src"
   for dep in $deps; do