ecpg: remove check_rules.pl.

As noted in the previous commit, check_rules.pl is now entirely
redundant with checks made by parse.pl, or would be if it weren't
for the places where it's wrong.  It's a waste of build cycles
and maintenance effort, so remove it.

Discussion: https://postgr.es/m/2011420.1713493114@sss.pgh.pa.us

Author: tglsfdc

src/interfaces/ecpg/preproc/Makefile

@@ -64,8 +64,7 @@ preproc.h: preproc.c
 
 preproc.c: BISONFLAGS += -d
 
-preproc.y: ../../../backend/parser/gram.y parse.pl check_rules.pl ecpg.addons ecpg.header ecpg.tokens ecpg.trailer ecpg.type
-	$(PERL) $(srcdir)/check_rules.pl --srcdir $(srcdir) --parser $<
+preproc.y: ../../../backend/parser/gram.y parse.pl ecpg.addons ecpg.header ecpg.tokens ecpg.trailer ecpg.type
 	$(PERL) $(srcdir)/parse.pl --srcdir $(srcdir) --parser $< --output $@
 
 # generate keyword headers

src/interfaces/ecpg/preproc/check_rules.pl

@@ -44,20 +44,6 @@ preproc_y = custom_target('preproc.y',
 )
 generated_sources += preproc_y
 
-check_rules = custom_target('preproc.y.check_rules',
-  input: [
-    '../../../backend/parser/gram.y',
-    ecpg_files,
-  ],
-  output: 'preproc.y.check_rules',
-  command: [
-    perl, files('check_rules.pl'),
-    '--srcdir', '@CURRENT_SOURCE_DIR@',
-    '--parser', '@INPUT0@',
-    '--stamp', '@OUTPUT0@',
-  ],
-)
-
 preproc = custom_target('preproc.c',
   input: preproc_y,
   kwargs: bison_kw,
@@ -68,7 +54,6 @@ ecpg_sources += preproc
 c_kwlist = custom_target('c_kwlist_d.h',
   input: ['c_kwlist.h'],
   output: ['c_kwlist_d.h'],
-  depends: check_rules,
   depend_files: gen_kwlist_deps,
   command: [gen_kwlist_cmd, '--varname', 'ScanCKeywords', '--no-case-fold'],
 )