Merge pull request ocaml#27999 from mbarbin/conf-hg

Add conf-hg

Author: mseri

packages/conf-hg/conf-hg.1.0/opam

@@ -0,0 +1,28 @@
+opam-version: "2.0"
+maintainer: "https://github.com/ocaml/opam-repository/issues"
+homepage: "https://www.mercurial-scm.org"
+authors: "Mercurial Developers"
+bug-reports: "https://github.com/ocaml/opam-repository/issues"
+license: "GPL-2.0-or-later"
+build: ["hg" "--version"]
+depexts: [
+  ["mercurial"] {os-family = "alpine"}
+  ["mercurial"] {os-family = "arch"}
+  ["mercurial"] {os-distribution = "centos"}
+  ["mercurial"] {os-family = "debian"}
+  ["mercurial"] {os-family = "fedora"}
+  ["mercurial"] {os = "freebsd"}
+  ["mercurial"] {os = "macos" & os-distribution = "homebrew"}
+  ["mercurial"] {os-distribution = "nixos"}
+  ["mercurial"] {os-distribution = "ol"}
+  ["mercurial"] {os = "openbsd"}
+  ["mercurial"] {os-family = "suse" | os-family = "opensuse"}
+  ["mercurial"] {os-family = "ubuntu"}
+  ["system:hg"] {os = "win32" & os-distribution = "cygwinports"}
+  ["mercurial"] {os = "win32" & os-distribution = "msys2"}
+  ["mercurial"] {os = "cygwin"}
+]
+synopsis: "Virtual package relying on hg"
+description:
+  "This package can only install if the hg program is installed on the system."
+flags: conf