IM debugging updates

- Control debugging via debug.h (previously im.c had its own
  defined constant to control this.)
- Remove reference to an undefined symbol im_event_fp within a DEBUG
  block.

Also:
- Explicitly include i18n.h required by im.c (though it appears to be
  getting included by another file indirectly.)  This should be a no-op
  change.

src/im.c

@@ -43,6 +43,12 @@
 #include <wchar.h>
 
 #include "im.h"
+#include "i18n.h"
+#include "debug.h"
+
+#ifdef DEBUG
+#include <assert.h>
+#endif
 
 
 /* ***************************************************************************
@@ -94,7 +100,9 @@ static const char *const im_tip_text[NUM_IM_TIPS] = {
 * CONSTANTS
 */
 
-/* #define IM_DEBUG       1 */
+#ifdef DEBUG
+#define IM_DEBUG         1
+#endif
 
 #define MAX_SECTIONS     8      /* Maximum numbers of sections in *.im file */
 #define MAX_UNICODE_SEQ 16      /* Output of state machine, including NUL */
@@ -1876,8 +1884,7 @@ void im_init(IM_DATA * im, int lang)
 
 #ifdef DEBUG
   assert(0 <= im->lang && im->lang < NUM_LANGS);
-  if (im_event_fp)
-    printf("Initializing IM for %s...\n", lang_prefixes[im->lang]);
+  printf("Initializing IM for %s...\n", lang_prefixes[im->lang]);
 #endif
 
   /* Initialize the individual IM */