download_and_compile.sh: use proper string comparison in _elementIn()

In Bash, the [[ <foo> == <bar> ]] and [[ <foo> = <bar> ]] conditionals
interpret <bar> as a shell globbing pattern. This wasn't desired in
_elementIn(), where the <bar> string is provided by the caller, and
might contain pattern metacharacters. Replace this conditional with a
plain string comparison made with '[' (aka, the 'test' command).

download_and_compile.sh

@@ -49,7 +49,7 @@ _elementIn(){
 
   shift
   for e; do
-    if [[ "$e" == "$valueToCheck" ]]; then
+    if [ "$e" = "$valueToCheck" ]; then
       return 0
     fi
   done