build(foreach): handle arguments robustly

Fix some shellcheck warnings and, more importantly, handle the arguments
more robustly by not word-splitting arguments. An invocation like
    foreach F "a b" c
would have run `F a; F b; F c`. Make it run `F "a b"; F c` as expected.

Author: benknoble

build.sh

@@ -118,8 +118,8 @@ build_6x_7x_old () {
 
 foreach () {
   declare -r command="${1}";
-  declare -r args="${@:2}";
-  for _arg in ${args}; do
+  declare -r args=("${@:2}");
+  for _arg in "${args[@]}"; do
     "${command}" "${_arg}";
   done;
 };