I suggest to try the search pattern "\<(?:(?:(.*))|([A-Z]+))" on source files. Some places will be found where names begin with two underscores or an underscore and an uppercase letter.

Examples: - __ADLIST_H__ - __DICT_H - __xstr

This does not fit to the expected naming conventions of the C language standard. I recommend to adjust your selection for unique names.

Comment From: yoav-steinberg

Even though this is technically correct, I think we're not going to handle this. In practice it's very common that projects don't follow this standard and the chances of a conflict with the standard libraries is very small. After 10 years I think we can safely close this.