Delete structs.h by spliting it and moving code to other headers

Here's the list of squashed commits (for more info, see PR #378).

 - Define guicolor_T as a typedef in syntax.h
 - Move a big chunk of code from structs.h to buffer_defs.h
 - Move aco_save_T from structs.h to fileio.h
 - Move option_table_T from structs.h to hardcopy.h

	Aditionally:

	 - Move the printer_opts global to hardcopy.c
	 - Delete structs.h. Include buffer_defs.h where structs.h was included
	   before.
	 - Add header guards to option_defs.h

 - Put mark types and constants in new mark_defs.h
 - Move undo structs to undo_defs.h
 - Move memfile structs to new memfile_defs.h
 - Move expand_T and cmdmod_T to ex_cmds_defs.h
 - Move memline_T to memline_defs.h
 - Move many defs and types to ex_eval.h
 - Move syntax related types to syntax_defs.h
 - Move struct memfile to memfile_defs.h
 - struct buffblock and struct buffheader moved back to buffer_defs.h
 - Move some datatypes to hashtab.h and eval_defs.h
 - Move the buffer_defs.h include and TODOs for remaining unrelated types in buffer_defs.h

1 files changed, 78 insertions, 0 deletions

diff --git a/src/syntax_defs.h b/src/syntax_defs.h
new file mode 100644
index 0000000000..6b16d64621
--- /dev/null
+++ b/src/syntax_defs.h
@@ -0,0 +1,78 @@
+#ifndef NEOVIM_SYNTAX_DEFS_H
+#define NEOVIM_SYNTAX_DEFS_H
+
+#include "regexp_defs.h"
+
+/* struct passed to in_id_list() */
+struct sp_syn {
+  int inc_tag;                  /* ":syn include" unique tag */
+  short id;                     /* highlight group ID of item */
+  short       *cont_in_list;    /* cont.in group IDs, if non-zero */
+};
+
+/*
+ * Each keyword has one keyentry, which is linked in a hash list.
+ */
+typedef struct keyentry keyentry_T;
+
+struct keyentry {
+  keyentry_T  *ke_next;         /* next entry with identical "keyword[]" */
+  struct sp_syn k_syn;          /* struct passed to in_id_list() */
+  short       *next_list;       /* ID list for next match (if non-zero) */
+  int flags;
+  int k_char;                   /* conceal substitute character */
+  char_u keyword[1];            /* actually longer */
+};
+
+/*
+ * Struct used to store one state of the state stack.
+ */
+typedef struct buf_state {
+  int bs_idx;                    /* index of pattern */
+  int bs_flags;                  /* flags for pattern */
+  int bs_seqnr;                  /* stores si_seqnr */
+  int bs_cchar;                  /* stores si_cchar */
+  reg_extmatch_T *bs_extmatch;   /* external matches from start pattern */
+} bufstate_T;
+
+/*
+ * syn_state contains the syntax state stack for the start of one line.
+ * Used by b_sst_array[].
+ */
+typedef struct syn_state synstate_T;
+
+struct syn_state {
+  synstate_T  *sst_next;        /* next entry in used or free list */
+  linenr_T sst_lnum;            /* line number for this state */
+  union {
+    bufstate_T sst_stack[SST_FIX_STATES];          /* short state stack */
+    garray_T sst_ga;            /* growarray for long state stack */
+  } sst_union;
+  int sst_next_flags;           /* flags for sst_next_list */
+  int sst_stacksize;            /* number of states on the stack */
+  short       *sst_next_list;   /* "nextgroup" list in this state
+                                 * (this is a copy, don't free it! */
+  disptick_T sst_tick;          /* tick when last displayed */
+  linenr_T sst_change_lnum;     /* when non-zero, change in this line
+                                 * may have made the state invalid */
+};
+
+/*
+ * Structure shared between syntax.c, screen.c and gui_x11.c.
+ */
+typedef struct attr_entry {
+  short ae_attr;                        /* HL_BOLD, etc. */
+  union {
+    struct {
+      char_u          *start;           /* start escape sequence */
+      char_u          *stop;            /* stop escape sequence */
+    } term;
+    struct {
+      /* These colors need to be > 8 bits to hold 256. */
+      short_u fg_color;                 /* foreground color number */
+      short_u bg_color;                 /* background color number */
+    } cterm;
+  } ae_u;
+} attrentry_T;
+
+#endif // NEOVIM_SYNTAX_DEFS_H