MFC r200626,201289,213764,214272, syncing yacc and flex to -CURRENT

r200626:
remove external reference to not (or at least no longer) existing variable 'myname'

r201289:
Let both yacc and lex generate code that passes -Wold-style-definition.

Both these tools emit code where several functions have no `void'
keyword placed in the arugment list when the function has no arguments.

r213764:
Don't define the input() function ifdef YY_NO_INPUT.
This was previously done for the input() function.

r214272:
flex: add missing ifdef magic to create/hide prototypes
This unbreaks build for some software with higher WARNS flags.