Enforce the first C standard

To ensure extensive compatibility among machines that have a C compiler,
the first C standard will be strictly enforced.
Replace one line comments with block comments

One line comments are not defined in the original C standard, so
instances of them must be replaced with block comments.
Don't mix declarations and code

The assignment statement was moved after the final variable declaration
for the main block.
Replace empty initializer braces with memset

ISO C forbids empty initializer braces.
Fixed many declaration after statement warnings

Moved declarations of many variables to the beginning of the function so
that the code complies with the first C standard. Some declarations have
not yet been moved because moving them will make the code more difficult
to read. Though they will need to be moved anyway, and since it is also
possible to declare variables at the beginning of a block (and not
necessarily only at the beginning of a function), it won't end up being
too unreadable after all.
Fixed some declaration after statement warnings

Still haven't tried fixing some declarations that first require a char *
to be incremented, which would require the variables to no longer be
declared const which would suck for readability. One possible strategy
is to maintain two pointers; a pointer to the current location in the
character array, and another pointer that points to the where the char *
should be pointing to after a performing a parsing function. If the two
character pointers are not equal (i.e. the second pointer now has a
greater value than the main pointer) then there were some tokens to
parse, and the main pointer should now be updated to point to where the
second pointer is. Repeat this process, stepping through the input
string with two character pointers. If this strategy maintains the
readability of the code while achieving ANSI C compliance at the same
time, then it might be a good implementation strategy.
Fixed some declaration after statement warnings
Fixed some declaration after statement warnings
Fixed some declaration after statement warnings
Use single field initializer for char array

Previously the character array expressionKeyword was initialized using
empty braces, which is valid for C++, but implemented as a GNU extension
for C. So a single field in the initializing braces is added to confirm
to ANSI C.
Fixed some declaration after statement warnings
Removed unnecessary local variable

Removing the variable EATEN_SPACE helps to partially fix the
"declaration after statement" warning reported for the function
parseNextToken.
Fixed declaration after statement warning