Fix wrong split function

The cases of this match were the wrong way around.

Combined with the previous fixes, this finally addressed #5838.

src/state/opamEnv.ml

@@ -156,9 +156,9 @@ let split_var ~(sepfmt:sep_path_format) var value =
     in
     let sep = OpamTypesBase.char_of_separator separator in
     match format with
-    | Target_quoted | Host_quoted ->
-      List.map (fun s -> (s, s, sep)) (OpamStd.String.split value sep)
     | Target | Host ->
+      List.map (fun s -> (s, s, sep)) (OpamStd.String.split value sep)
+    | Target_quoted | Host_quoted ->
       let split_path_variable path =
         let length = String.length path in
         let rec f acc index current current_raw last normal =

tests/reftests/env.win32.test

@@ -27,6 +27,7 @@ set "PATH=${BASEDIR}/OPAM/rewriting/bin;C:\Devel\bin1;C:\Devel\bin2;"C:\Devel\bi
 ### opam env | grep MANPATH
 MANPATH=':"${BASEDIR}/OPAM/rewriting/man"'; export MANPATH;
 ### opam exec -- opam env --revert | grep MANPATH
+MANPATH=''; export MANPATH;
 ### : Tests forward and backslash rewriting on revert
 ### : This sequence of updates is what presently happens with the compiler
 ### <pkg:mixed-updates.1>