Add some extra stub modules.

Also for use in test programs: stub modules that provide non-
functional versions of logging, printing and storage.

stubs/no-logging.c

@@ -0,0 +1,20 @@
+/*
+ * Stub module implementing the logging API for tools that don't do
+ * session logging.
+ */
+
+#include "putty.h"
+
+void logtraffic(LogContext *ctx, unsigned char c, int logmode) {}
+void logflush(LogContext *ctx) {}
+void logevent(LogContext *ctx, const char *event) {}
+void log_free(LogContext *ctx) {}
+void log_reconfig(LogContext *ctx, Conf *conf) {}
+void log_packet(LogContext *ctx, int direction, int type,
+                const char *texttype, const void *data, size_t len,
+                int n_blanks, const struct logblank_t *blanks,
+                const unsigned long *seq,
+                unsigned downstream_id, const char *additional_log_text) {}
+
+LogContext *log_init(LogPolicy *lp, Conf *conf)
+{ return NULL; }

stubs/no-printing.c

@@ -0,0 +1,18 @@
+/*
+ * Stub module implementing the printing API for tools that don't
+ * print.
+ */
+
+#include "putty.h"
+
+printer_job *printer_start_job(char *printer) { return NULL; }
+void printer_job_data(printer_job *pj, const void *data, size_t len) {}
+void printer_finish_job(printer_job *pj) {}
+
+printer_enum *printer_start_enum(int *nprinters_ptr)
+{
+    *nprinters_ptr = 0;
+    return NULL;
+}
+char *printer_get_name(printer_enum *pe, int i) { return NULL; }
+void printer_finish_enum(printer_enum *pe) {}

stubs/no-storage.c

@@ -0,0 +1,40 @@
+/*
+ * Stub module implementing the saved-session storage APIs for tools
+ * that don't load or save sessions.
+ */
+
+#include "putty.h"
+
+settings_w *open_settings_w(const char *sessionname, char **errmsg)
+{ return NULL; }
+void write_setting_s(settings_w *handle, const char *key, const char *value)
+{ unreachable("where did you get a settings_w from?"); }
+void write_setting_i(settings_w *handle, const char *key, int value)
+{ unreachable("where did you get a settings_w from?"); }
+void write_setting_fontspec(settings_w *handle, const char *name, FontSpec *fs)
+{ unreachable("where did you get a settings_w from?"); }
+void write_setting_filename(settings_w *handle, const char *name, Filename *fn)
+{ unreachable("where did you get a settings_w from?"); }
+void close_settings_w(settings_w *handle)
+{ unreachable("where did you get a settings_w from?"); }
+
+settings_r *open_settings_r(const char *sessionname)
+{ return NULL; }
+char *read_setting_s(settings_r *handle, const char *key)
+{ return NULL; }
+int read_setting_i(settings_r *handle, const char *key, int defvalue)
+{ return defvalue; }
+FontSpec *read_setting_fontspec(settings_r *handle, const char *name)
+{ return fontspec_new_default(); }
+Filename *read_setting_filename(settings_r *handle, const char *name)
+{ return filename_from_str(""); }
+void close_settings_r(settings_r *handle) { }
+
+void del_settings(const char *sessionname) {}
+
+settings_e *enum_settings_start(void)
+{ return NULL; }
+bool enum_settings_next(settings_e *handle, strbuf *out)
+{ unreachable("where did you get a settings_e from?"); }
+void enum_settings_finish(settings_e *handle)
+{ unreachable("where did you get a settings_e from?"); }