Add symbol imports file

test_symbols.sh

@@ -7,7 +7,7 @@ set -euo pipefail
 diff -u <(sort < "$2") <(nm "$1" | grep " T " | cut -f3 -d " " | sort)
 ec=0
 for symbol in $(nm "$1" | grep " U " | sed 's/ U //') ; do
-    if ! grep "$symbol" "$3" > /dev/null ; then
+    if ! grep --fixed-strings "$symbol" "$3" > /dev/null ; then
         echo "Imported symbol $symbol not present in $3"
         ec=1
     fi