[Fix] set -a: when this option is set, some sh shells break

Fixes #2574

Author: ljharb

nvm.sh

@@ -2661,6 +2661,13 @@ nvm() {
     EXIT_CODE="$?"
     set -e
     return "$EXIT_CODE"
+  elif [ "${-#*a}" != "$-" ]; then
+    set +a
+    local EXIT_CODE
+    IFS="${DEFAULT_IFS}" nvm "$@"
+    EXIT_CODE="$?"
+    set -a
+    return "$EXIT_CODE"
   elif [ "${IFS}" != "${DEFAULT_IFS}" ]; then
     IFS="${DEFAULT_IFS}" nvm "$@"
     return "$?"