Rename most of the platform source files.

This gets rid of all those annoying 'win', 'ux' and 'gtk' prefixes
which made filenames annoying to type and to tab-complete. Also, as
with my other recent renaming sprees, I've taken the opportunity to
expand and clarify some of the names so that they're not such cryptic
abbreviations.

unix/gss.c

@@ -0,0 +1,175 @@
+#include "putty.h"
+#ifndef NO_GSSAPI
+#include "ssh/pgssapi.h"
+#include "ssh/gss.h"
+#include "ssh/gssc.h"
+
+/* Unix code to set up the GSSAPI library list. */
+
+#if !defined NO_LIBDL && !defined STATIC_GSSAPI && !defined NO_GSSAPI
+
+const int ngsslibs = 4;
+const char *const gsslibnames[4] = {
+    "libgssapi (Heimdal)",
+    "libgssapi_krb5 (MIT Kerberos)",
+    "libgss (Sun)",
+    "User-specified GSSAPI library",
+};
+const struct keyvalwhere gsslibkeywords[] = {
+    { "libgssapi", 0, -1, -1 },
+    { "libgssapi_krb5", 1, -1, -1 },
+    { "libgss", 2, -1, -1 },
+    { "custom", 3, -1, -1 },
+};
+
+/*
+ * Run-time binding against a choice of GSSAPI implementations. We
+ * try loading several libraries, and produce an entry in
+ * ssh_gss_libraries[] for each one.
+ */
+
+static void gss_init(struct ssh_gss_library *lib, void *dlhandle,
+                     int id, const char *msg)
+{
+    lib->id = id;
+    lib->gsslogmsg = msg;
+    lib->handle = dlhandle;
+
+#define BIND_GSS_FN(name) \
+    lib->u.gssapi.name = (t_gss_##name) dlsym(dlhandle, "gss_" #name)
+
+    BIND_GSS_FN(delete_sec_context);
+    BIND_GSS_FN(display_status);
+    BIND_GSS_FN(get_mic);
+    BIND_GSS_FN(verify_mic);
+    BIND_GSS_FN(import_name);
+    BIND_GSS_FN(init_sec_context);
+    BIND_GSS_FN(release_buffer);
+    BIND_GSS_FN(release_cred);
+    BIND_GSS_FN(release_name);
+    BIND_GSS_FN(acquire_cred);
+    BIND_GSS_FN(inquire_cred_by_mech);
+
+#undef BIND_GSS_FN
+
+    ssh_gssapi_bind_fns(lib);
+}
+
+/* Dynamically load gssapi libs. */
+struct ssh_gss_liblist *ssh_gss_setup(Conf *conf)
+{
+    void *gsslib;
+    char *gsspath;
+    struct ssh_gss_liblist *list = snew(struct ssh_gss_liblist);
+
+    list->libraries = snewn(4, struct ssh_gss_library);
+    list->nlibraries = 0;
+
+    /* Heimdal's GSSAPI Library */
+    if ((gsslib = dlopen("libgssapi.so.2", RTLD_LAZY)) != NULL)
+        gss_init(&list->libraries[list->nlibraries++], gsslib,
+                 0, "Using GSSAPI from libgssapi.so.2");
+
+    /* MIT Kerberos's GSSAPI Library */
+    if ((gsslib = dlopen("libgssapi_krb5.so.2", RTLD_LAZY)) != NULL)
+        gss_init(&list->libraries[list->nlibraries++], gsslib,
+                 1, "Using GSSAPI from libgssapi_krb5.so.2");
+
+    /* Sun's GSSAPI Library */
+    if ((gsslib = dlopen("libgss.so.1", RTLD_LAZY)) != NULL)
+        gss_init(&list->libraries[list->nlibraries++], gsslib,
+                 2, "Using GSSAPI from libgss.so.1");
+
+    /* User-specified GSSAPI library */
+    gsspath = conf_get_filename(conf, CONF_ssh_gss_custom)->path;
+    if (*gsspath && (gsslib = dlopen(gsspath, RTLD_LAZY)) != NULL)
+        gss_init(&list->libraries[list->nlibraries++], gsslib,
+                 3, dupprintf("Using GSSAPI from user-specified"
+                              " library '%s'", gsspath));
+
+    return list;
+}
+
+void ssh_gss_cleanup(struct ssh_gss_liblist *list)
+{
+    int i;
+
+    /*
+     * dlopen and dlclose are defined to employ reference counting
+     * in the case where the same library is repeatedly dlopened, so
+     * even in a multiple-sessions-per-process context it's safe to
+     * naively dlclose everything here without worrying about
+     * destroying it under the feet of another SSH instance still
+     * using it.
+     */
+    for (i = 0; i < list->nlibraries; i++) {
+        dlclose(list->libraries[i].handle);
+        if (list->libraries[i].id == 3) {
+            /* The 'custom' id involves a dynamically allocated message.
+             * Note that we must cast away the 'const' to free it. */
+            sfree((char *)list->libraries[i].gsslogmsg);
+        }
+    }
+    sfree(list->libraries);
+    sfree(list);
+}
+
+#elif !defined NO_GSSAPI
+
+const int ngsslibs = 1;
+const char *const gsslibnames[1] = {
+    "static",
+};
+const struct keyvalwhere gsslibkeywords[] = {
+    { "static", 0, -1, -1 },
+};
+
+/*
+ * Link-time binding against GSSAPI. Here we just construct a single
+ * library structure containing pointers to the functions we linked
+ * against.
+ */
+
+#include <gssapi/gssapi.h>
+
+/* Dynamically load gssapi libs. */
+struct ssh_gss_liblist *ssh_gss_setup(Conf *conf)
+{
+    struct ssh_gss_liblist *list = snew(struct ssh_gss_liblist);
+
+    list->libraries = snew(struct ssh_gss_library);
+    list->nlibraries = 1;
+
+    list->libraries[0].gsslogmsg = "Using statically linked GSSAPI";
+
+#define BIND_GSS_FN(name) \
+    list->libraries[0].u.gssapi.name = (t_gss_##name) gss_##name
+
+    BIND_GSS_FN(delete_sec_context);
+    BIND_GSS_FN(display_status);
+    BIND_GSS_FN(get_mic);
+    BIND_GSS_FN(verify_mic);
+    BIND_GSS_FN(import_name);
+    BIND_GSS_FN(init_sec_context);
+    BIND_GSS_FN(release_buffer);
+    BIND_GSS_FN(release_cred);
+    BIND_GSS_FN(release_name);
+    BIND_GSS_FN(acquire_cred);
+    BIND_GSS_FN(inquire_cred_by_mech);
+
+#undef BIND_GSS_FN
+
+    ssh_gssapi_bind_fns(&list->libraries[0]);
+
+    return list;
+}
+
+void ssh_gss_cleanup(struct ssh_gss_liblist *list)
+{
+    sfree(list->libraries);
+    sfree(list);
+}
+
+#endif /* NO_LIBDL */
+
+#endif /* NO_GSSAPI */