Implement a function that reads a string encoding an integer in a given base and returns its decimal value.

• The function receives a string and a base between 2 and 16.
• Skip any leading whitespace characters (ASCII value 32 or below) before the first digit.
• A single leading + or - sign may appear before the digits and sets the result sign accordingly.
• Digits are 0-9 for value 0-9, and a-f or A-F for value 10-15, case-insensitive.
• Stop consuming characters as soon as one is not a valid digit for the given base.
• Return the parsed integer as a base-10 int.
• The prototype is int parse_int_base(const char *str, int base);.
• No external libraries are allowed.

Implement a function that reads a string encoding an integer in a given base and returns its decimal value.

• The function receives a string and a base between 2 and 16.
• Skip any leading whitespace characters (ASCII value 32 or below) before the first digit.
• A single leading + or - sign may appear before the digits and sets the result sign accordingly.
• Digits are 0-9 for value 0-9, and a-f or A-F for value 10-15, case-insensitive.
• Stop consuming characters as soon as one is not a valid digit for the given base.
• Return the parsed integer as a base-10 int.
• The prototype is int parse_int_base(const char *str, int base);.
• No external libraries are allowed.