repeat operators allowed to start regular expression

[andrei-diaconu]

Repeat operator (*, & and +) characters are allowed in the beginning of the regular expression. According to the documentation they should be followed by an atom. Also, all the other regex engines I tested report this as error in the regular expression.

Example: "*_abc" is considered by regcomp a valid regular expression, and matches "_abc".

I believe regcomp should report compile error, just like for other improper expressions, like "(_abc".