User options:
a	no warnings or stricts
A	while running preprocessor, generate makefile dependencies
C	while running preprocessor, copy comment
d	perform a small dataflow analysis
D	see identifier following as a macro
E	run preprocessor only
g	produce symbol table for debugger
i	suppress /usr/include include files in dependency list
I	expand include table with directory name following
m	generate file.o: file1.h format dependency lines
M	set identifier length
n	don't generate register messages
L	don't generate linenumbers and filename indications
o	no warnings or stricts about normal old-style constuctions
p	trace
P	in running the preprocessor do not output '# line' lines
s	no stricts
S	switch density
T	take path following as directory for storing temporary file(s)
U	undefine predefined name
V	set objectsize and alignment requirements
w	suppress warning diagnostics


Debug options:

f	dump whole identifier table, including macros and reserved words
h	supply hash table statistics
i	print name of include files
r	right-adjust bitfield
t	dump table of identifiers
u	unstack L_UNIVERSAL
x	dump expressions