Generate fmgr prototypes automatically

Gen_fmgrtab.pl creates a new file fmgrprotos.h, which contains
prototypes for all functions registered in pg_proc.h.  This avoids
having to manually maintain these prototypes across a random variety of
header files.  It also automatically enforces a correct function
signature, and since there are warnings about missing prototypes, it
will detect functions that are defined but not registered in
pg_proc.h (or otherwise used).

Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>

src/backend/tsearch/dict_ispell.c

@@ -17,6 +17,7 @@
 #include "tsearch/dicts/spell.h"
 #include "tsearch/ts_locale.h"
 #include "tsearch/ts_utils.h"
+#include "utils/builtins.h"
 
 
 typedef struct

src/backend/tsearch/dict_simple.c

@@ -16,6 +16,7 @@
 #include "commands/defrem.h"
 #include "tsearch/ts_locale.h"
 #include "tsearch/ts_utils.h"
+#include "utils/builtins.h"
 
 
 typedef struct

src/backend/tsearch/dict_synonym.c

@@ -16,6 +16,7 @@
 #include "commands/defrem.h"
 #include "tsearch/ts_locale.h"
 #include "tsearch/ts_utils.h"
+#include "utils/builtins.h"
 
 typedef struct
 {

src/backend/tsearch/ts_selfuncs.c

@@ -19,6 +19,7 @@
 #include "miscadmin.h"
 #include "nodes/nodes.h"
 #include "tsearch/ts_type.h"
+#include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/selfuncs.h"
 #include "utils/syscache.h"