Support C++14 quoted integer literals

[Zenju]

Hi,

unifdef works great with my C++20 code base! There is just a minor issue with C++14 quoted integer literals: "Unterminated char literal", e.g. when a C++ source file contains: int num = 1'000'000;

The patch adds support und appears to work fine in my tests. Still it would be great if you could give it a quick review:

When quotes are detected inside an integer literal, the patch skips two characters until after the quote. This seems against the spirit of a function named "skipcomment()", because (part of) an integer literal is skipped, not a comment. Still I believe this should be fine, as the code calling skipcomment() only cares about preprocessor statements, and integer literals are not that. Is this assumption correct?

Best, Zenju

[xyshal]

Seems like you could also just not flag the beginning of a char literal if the previous char was a digit, or something like that?

diff --git a/unifdef.c b/unifdef.c
index dc145a2..d73dd5e 100644
--- a/unifdef.c
+++ b/unifdef.c
@@ -1260,6 +1260,7 @@ skipcomment(const char *cp)
                                incomment = CXX_COMMENT;
                                cp += 2;
                        } else if (strncmp(cp, "\'", 1) == 0) {
+                               if (isdigit((unsigned char)*(cp-1))) return cp;
                                incomment = CHAR_LITERAL;
                                linestate = LS_DIRTY;
                                cp += 1;