Hi! 👋

I package libgit2 for Arch Linux.
With 1.8.1 I noticed, that the library is no longer built using the system-provided http-parser, when using the relevant cmake option as documented:

Instead -D USE_HTTP_PARSER=http-parser must be used to build against a system-provided http-parser.

This regression was introduced in d396819 (from what I can tell).

It would be good to a) consolidate the documentation accordingly, or change the way the new integration interacts with USE_HTTP_PARSER, b) fail if a wrong value is provided to an option and c) not silently choose a bundled version but instead hard fail (silently building with something different is never what downstreams want, if they explicitly selected to build against a system version).

Reproduction steps

Use cmake option -D USE_HTTP_PARSER=system to build with system provided http-parser, as documented in CMakeLists.txt.

Expected behavior

libgit2 is built with system provided http-parser.

Actual behavior

libgit2 is (silently!) built with bundled http-parser.

Version of libgit2 (release number or SHA1)

1.8.2 (1.8.1 is also affected).

Operating system(s) tested

Arch Linux