Describe -w option.
* Option `-fpreprocessed` means skipping preprocessor for C files
* Option `-fsyntax-only` means stopping after parsing and semantic
checking of C files without MIR code generation
+ * Option `-w` means switching off reporting all warnings
* Option `-pedantic` is used for stricter diagnostic about C
standard conformance. It might be useful as C2MIR implements some GCC extensions of C
* Option `-O<n>` is used to set up MIR-generator optimization level. The optimization levels are described
