preproc: Move Preproc type to preproc_ops structure

There is no need to hide this structure into a type.
The former preproc_ops is a way more descriptive.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

nasm.c

@@ -122,7 +122,8 @@ static struct RAA *offsets;
 static struct SAA *forwrefs;    /* keep track of forward references */
 static const struct forwrefinfo *forwref;
 
-static Preproc *preproc;
+static struct preproc_ops *preproc;
+
 enum op_type {
     op_normal,                  /* Preprocess and assemble */
     op_preprocess,              /* Preprocess only */
@@ -168,10 +169,11 @@ static const struct warning {
  * not preprocess their source file.
  */
 
-static void no_pp_reset(char *, int, ListGen *, StrList **);
+static void no_pp_reset(char *file, int pass, ListGen *listgen, StrList **deplist);
 static char *no_pp_getline(void);
-static void no_pp_cleanup(int);
-static Preproc no_pp = {
+static void no_pp_cleanup(int pass);
+
+static struct preproc_ops no_pp = {
     no_pp_reset,
     no_pp_getline,
     no_pp_cleanup

nasm.h

@@ -352,28 +352,28 @@ typedef struct string_list {
 /*
  * preprocessors ought to look like this:
  */
-typedef struct preproc_ops {
+struct preproc_ops {
     /*
      * Called at the start of a pass; given a file name, the number
      * of the pass, an error reporting function, an evaluator
      * function, and a listing generator to talk to.
      */
-    void (*reset) (char *, int, ListGen *, StrList **);
+    void (*reset)(char *file, int pass, ListGen *listgen, StrList **deplist);
 
     /*
      * Called to fetch a line of preprocessed source. The line
      * returned has been malloc'ed, and so should be freed after
      * use.
      */
-    char *(*getline) (void);
+    char *(*getline)(void);
 
     /*
      * Called at the end of a pass.
      */
-    void (*cleanup) (int);
-} Preproc;
+    void (*cleanup)(int pass);
+};
 
-extern Preproc nasmpp;
+extern struct preproc_ops nasmpp;
 
 /*
  * ----------------------------------------------------------------

preproc.c

@@ -5505,7 +5505,7 @@ static void make_tok_num(Token * tok, int64_t val)
     tok->type = TOK_NUMBER;
 }
 
-Preproc nasmpp = {
+struct preproc_ops nasmpp = {
     pp_reset,
     pp_getline,
     pp_cleanup