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, 12 insertions, 9 deletions

diff --git a/load.c b/load.c
index 9a83829..f20c1c7 100644
--- a/load.c
+++ b/load.c
@@ -32,11 +32,13 @@ this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 static load_func_t
 load_object (const gmk_floc *flocp, int noerror,
-             const char *ldname, const char *symname)
+             const char *ldname, const char *symname, void **dlp)
 {
   static void *global_dl = NULL;
   load_func_t symp;
 
+  *dlp = NULL;
+
   if (! global_dl)
     {
       global_dl = dlopen (NULL, RTLD_NOW|RTLD_GLOBAL);
@@ -46,7 +48,6 @@ load_object (const gmk_floc *flocp, int noerror,
 
   symp = (load_func_t) dlsym (global_dl, symname);
   if (! symp) {
-    void *dlp = NULL;
 
     /* If the path has no "/", try the current directory first.  */
     if (! strchr (ldname, '/')
@@ -54,14 +55,14 @@ load_object (const gmk_floc *flocp, int noerror,
 	&& ! strchr (ldname, '\\')
 #endif
 	)
-      dlp = dlopen (concat (2, "./", ldname), RTLD_LAZY|RTLD_GLOBAL);
+      *dlp = dlopen (concat (2, "./", ldname), RTLD_LAZY|RTLD_GLOBAL);
 
     /* If we haven't opened it yet, try the default search path.  */
-    if (! dlp)
-      dlp = dlopen (ldname, RTLD_LAZY|RTLD_GLOBAL);
+    if (! *dlp)
+      *dlp = dlopen (ldname, RTLD_LAZY|RTLD_GLOBAL);
 
     /* Still no?  Then fail.  */
-    if (! dlp)
+    if (! *dlp)
       {
         if (noerror)
           DB (DB_BASIC, ("%s", dlerror()));
@@ -70,7 +71,7 @@ load_object (const gmk_floc *flocp, int noerror,
         return NULL;
       }
 
-    symp = dlsym (dlp, symname);
+    symp = dlsym (*dlp, symname);
     if (! symp)
       fatal (flocp, _("Failed to load symbol %s from %s: %s"),
              symname, ldname, dlerror());
@@ -80,7 +81,7 @@ load_object (const gmk_floc *flocp, int noerror,
 }
 
 int
-load_file (const gmk_floc *flocp, const char **ldname, int noerror)
+load_file (const gmk_floc *flocp, const char **ldname, int noerror, void **dlp)
 {
   int nmlen = strlen (*ldname);
   char *new = alloca (nmlen + CSTRLEN (SYMBOL_EXTENSION) + 1);
@@ -90,6 +91,8 @@ load_file (const gmk_floc *flocp, const char **ldname, int noerror)
   int r;
   load_func_t symp;
 
+  *dlp = NULL;
+
   /* Break the input into an object file name and a symbol name.  If no symbol
      name was provided, compute one from the object file name.  */
   fp = strchr (*ldname, '(');
@@ -165,7 +168,7 @@ load_file (const gmk_floc *flocp, const char **ldname, int noerror)
   DB (DB_VERBOSE, (_("Loading symbol %s from %s\n"), symname, *ldname));
 
   /* Load it!  */
-  symp = load_object(flocp, noerror, *ldname, symname);
+  symp = load_object(flocp, noerror, *ldname, symname, dlp);
   if (! symp)
     return 0;