Lookup at gpatch before patch on macOS now that both homebrew and mac…

…ports expose gpatch as gpatch

Homebrew changed behaviour in Homebrew/homebrew-core#174687

.github/workflows/ci.ml

@@ -333,6 +333,7 @@ let main_build_job ~analyse_job ~cygwin_job ?section runner start_version ~oc ~w
   let host = host_of_platform platform in
   job ~oc ~workflow ~runs_on:(Runner [runner]) ?shell ?section ~needs ~matrix ("Build-" ^ name_of_platform platform)
     ++ only_on Linux (run "Install bubblewrap" ["sudo apt install bubblewrap"])
+    ++ only_on MacOS (run "Install GNU patch" ["brew install gpatch"])
     ++ only_on Windows (git_lf_checkouts ~cond:(Predicate(true, EndsWith("matrix.host", "-pc-cygwin"))) ~shell:"cmd" ~title:"Configure LF checkout for Cygwin" ())
     ++ checkout ()
     ++ only_on Windows (cache ~cond:(Predicate(true, Compare("matrix.build", "x86_64-pc-cygwin"))) Cygwin)

.github/workflows/main.yml

@@ -245,6 +245,8 @@ jobs:
         ocamlv: [ 4.14.2, 5.2.0 ]
       fail-fast: true
     steps:
+    - name: Install GNU patch
+      run: brew install gpatch
     - name: Checkout tree
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache

master_changes.md

@@ -66,6 +66,7 @@ users)
 ## Opamfile
 
 ## External dependencies
+  * Lookup at `gpatch` before `patch` on macOS now that both homebrew and macports expose `gpatch` as `gpatch` since Homebrew/homebrew-core#174687 [#6255 @kit-ty-kate]
 
 ## Format upgrade
 

src/core/opamSystem.ml

@@ -1570,12 +1570,12 @@ let gpatch = lazy begin
   in
   let default_cmd, other_cmds =
     match OpamStd.Sys.os () with
+    | Darwin
     | DragonFly
     | FreeBSD
     | NetBSD
     | OpenBSD -> ("gpatch", ["patch"])
     | Cygwin
-    | Darwin
     | Linux
     | Unix
     | Win32