--E Run only the C preprocessor. Preprocess all the C source
-files specified and output the results to standard output.
-
--M Tell the preprocessor to output a rule suitable for make
-describing the dependencies of each object file. For each
-source file, the preprocessor outputs one make-rule whose
-target is the object file name for that source file and
-whose dependencies are all the files `#include'd in it.
-This rule may be a single line or may be continued with
-`\'-newline if it is long. The list of rules is printed on
-standard output instead of the preprocessed C program. `-M'
-implies `-E'.
-
--C Tell the preprocessor not to discard comments. Used with
-the `-E' option.
-
--MM Like `-M' but the output mentions only the user header
-files included with `#include "file"'.
-System header files included with `#include <file>' are
-omitted.
-
--Aquestion(answer) Assert the answer answer for question,
-in case it is tested with a preprocessor conditional such
-as `#if #question(answer)'. `-A-' disables the standard
-assertions that normally describe the target machine.
-
--Aquestion (answer) Assert the answer answer for question,
-in case it is tested with a preprocessor conditional such
-as `#if #question(answer)'. `-A-' disables the standard
-assertions that normally describe the target machine.
-
--Umacro Undefine macro macro. `-U' options are evaluated
-after all `-D' options, but before any `-include' and `-imacros'
-options.
-
--dM Tell the preprocessor to output only a list of the macro
-definitions that are in effect at the end of preprocessing.
-Used with the `-E' option.
-
--dD Tell the preprocessor to pass all macro definitions into
-the output, in their proper sequence in the rest of the
-output.
-
--dN Like `-dD' except that the macro arguments and contents
-are omitted. Only `#define name' is included in the output.
-