extended version of gnu bc.
I added several features to bc to make it more useful for me:
- fixed some warnings and errors in bc.y when compiling with bison
- added bitwise |, &, ~ operators ( or, and, xor )
- added support for 0xhexval input, when 0xhexval constants
are found, output is printed in both hex, and decimal.
- added '-e' option, to evaluate expression from commandline
- made to compile with readline versions >=4.3