Revert "Merge pull request #13029 from dra27/windows-zstd"

This reverts commit 3a176d7.

Author: dra27

configure

@@ -2234,41 +2234,6 @@ AS_IF([test x"$with_zstd" != "xno"],
         [[#include <zstd.h>]])],
       [zstd_status="zstd library not found"])]))
 
-# When building the mingw-w64 port in Cygwin, it is very easy to have the
-# library available, but not have the DLL in PATH. This then causes the build to
-# fail as soon as ocamlrun is first executed. This check avoids automatically
-# enabling zstd when the resulting executable doesn't actually work.
-AS_CASE([$host],
-  [*-w64-mingw32*|*-pc-windows],
-    [AS_IF([test x"$build" = x"$host"],[
-      check_zstd_runs=true],[
-      AS_CASE([$build],
-       [*-pc-msys|*-pc-cygwin*],
-         [check_zstd_runs=true],
-       [check_zstd_runs=false])
-    ])],
-  [check_zstd_runs=false])
-
-AS_IF([test x"$zstd_status" = "xok"],[
-  AC_MSG_CHECKING([whether programs linked zstd can execute])
-  AS_IF([! $check_zstd_runs],[
-    AC_MSG_RESULT([skipped])],[
-    OCAML_CC_SAVE_VARIABLES
-    LIBS="$LIBS $zstd_libs"
-    CFLAGS="$CFLAGS $zstd_flags"
-    OCAML_RUN_IFELSE(
-      [AC_LANG_SOURCE([[
-#include <zstd.h>
-int main(void) {
-  return (ZSTD_versionNumber() == 0);
-}
-      ]])],
-      [AC_MSG_RESULT([yes])],
-      [AC_MSG_RESULT([no])
-      zstd_status="programs linked with zstd do not appear to be executable."],
-      [AC_MSG_RESULT([skipped])])
-    OCAML_CC_RESTORE_VARIABLES])])
-
 AS_IF([test x"$zstd_status" = "xok"],
   [AC_MSG_NOTICE([compressed compilation artefacts supported])
    internal_cppflags="$internal_cppflags $zstd_flags"