& escaped as &#xamp; instead of & in links to URLs with query strings

[AnyOldName3]

This is a regression since the upstream 3.49.2 release that Windows binaries are provided for - that would write &. I've not been able to determine when the regression was introduced as it wasn't obvious from the diffs for individual commits or overall diff, and C and French aren't my usual languages.

This isn't just a stylistic problem - &#xamp; isn't valid HTML, and doesn't produce an ampersand. The things that do are &, & and &.

This is a before and after for a website first done with upstream 3.49.2, and redone with the master branch of this fork:

In regular text, ampersands are left alone with the escaping (or lack thereof) they had originally, so it seems to be something related to how URLs are extracted and replaced.

[AnyOldName3]

Looks like it was #10, and the new escaping function added by that MR never worked properly. This change fixes it:

diff --git a/src/htslib.c b/src/htslib.c
index e900a3c..a17c1af 100644
--- a/src/htslib.c
+++ b/src/htslib.c
@@ -3914,8 +3914,10 @@ HTSEXT_API size_t x_escape_flags(const char* const s, char* const dest, const si
 		} else {
 			if (flags & ENCODE_PARAMS_AS_HTML_ENTITIES) {
 				ADD_CHAR('&');
-				ADD_CHAR('#');
-				ADD_CHAR('x');
+				if (c != '&') {
+					ADD_CHAR('#');
+					ADD_CHAR('x');
+				}
 			} else
 				ADD_CHAR('%');
 			if (c != '&' || (flags & ENCODE_PARAMS_AS_HTML_ENTITIES) == FALSE) {

This might not apply cleanly as I'd monkey-patched something else in the same file, so the line numbers won't match.