tccpp: cleanup #include_next

tcc_normalize_inc_dirs: normally no problem to be absolutly
gcc compatible as long as it can be done the tiny way.

This reverts to the state before recent related commits and
reimplements a (small) part of it to fix the reported problem.


Also: Revert "parsing "..." sequence"
c3975cf27c

	&& p[1] == '.'

is not a reliable way to lookahead

tcc.h

@@ -536,10 +536,10 @@ typedef struct BufferedFile {
     struct BufferedFile *prev;
     int line_num;    /* current line number - here to simplify code */
     int line_ref;    /* tcc -E: last printed line */
-    int inc_path_index;
     int ifndef_macro;  /* #ifndef macro / #endif search */
     int ifndef_macro_saved; /* saved ifndef_macro */
     int *ifdef_stack_ptr; /* ifdef_stack value at the start of the file */
+    int include_next_index; /* next search path */
     char filename[1024];    /* filename */
     unsigned char unget[4];
     unsigned char buffer[1]; /* extra size for CH_EOB char */