Fix interfacing with and remaking dynamic objects on MS-Windows.

 load.c (load_object, load_file): Accept an additional argument
 DLP and return in it a pointer that can be used to unload the
 dynamic object.
 read.c (eval): Call load_file with an additional argument, and
 record the pointer returned there in the 'struct file' object of
 dynamic objects in that object's 'struct file'.
 commands.c (execute_file_commands): Unload dynamic objects
 before remaking them, to avoid failure to remake if the OS doesn't
 allow overwriting objects that are in use.
 filedef.h (struct file): New member dlopen_ptr.
 gnumake.h (GMK_EXPORT): Define to dllexport/dllimport
 decorations for Windows and to nothing on other platforms.
 (gmk_eval, gmk_expand, gmk_add_function): Add GMK_EXPORT qualifier
 to prototypes.
 makeint.h (MAIN): Define before including gnumake.h, to give
 correct dllexport decorations to exported functions.
 (load_file): Adjust prototype.
 loadapi.c: Don't include gnumake.h, since makeint.h already
 includes it, and takes care of defining MAIN before doing so.
 build_w32.bat (LinkGCC): Produce an import library for functions
 exported by Make for loadable dynamic objects.

 w32/compat/posixfcn.c (dlclose): New function.
 w32/include/dlfcn.h (dlclose): Add prototype.

 scripts/features/load: Fix signatures of testload_gmk_setup and
 explicit_setup, to bring them in line with the documentation.

1 files changed, 3 insertions, 1 deletions

diff --git a/read.c b/read.c
index b74e4a9..50f8414 100644
--- a/read.c
+++ b/read.c
@@ -937,11 +937,12 @@ eval (struct ebuffer *ebuf, int set_default)
               struct nameseq *next = files->next;
               const char *name = files->name;
               struct dep *deps;
+              void *dlp;
 
               free_ns (files);
               files = next;
 
-              if (! load_file (&ebuf->floc, &name, noerror) && ! noerror)
+              if (! load_file (&ebuf->floc, &name, noerror, &dlp) && ! noerror)
                 fatal (&ebuf->floc, _("%s: failed to load"), name);
 
               deps = alloc_dep ();
@@ -950,6 +951,7 @@ eval (struct ebuffer *ebuf, int set_default)
               deps->file = lookup_file (name);
               if (deps->file == 0)
                 deps->file = enter_file (name);
+              deps->file->dlopen_ptr = dlp;
             }
 
           continue;