build: Drop make syntax-check

As of lately it emits a ton of errors from `grep` about having `*`
at the start of a line, but more generally it's only generally
found papercut-style issues that aren't worth carrying a distinct
checking system for.

.cci.jenkinsfile

@@ -20,7 +20,6 @@ stage("Build") {
         try {
           shwrap("""
             make check
-            make syntax-check
           """)
         } finally {
             shwrap("cat test-suite.log || true")

GNUmakefile

@@ -40,8 +40,6 @@ include Makefile
 _build-aux ?= build-aux
 _autoreconf ?= autoreconf -v
 
-include $(srcdir)/maint.mk
-
 # Ensure that $(VERSION) is up to date for dist-related targets, but not
 # for others: rerunning autoreconf and recompiling everything isn't cheap.
 _have-git-version-gen := \
@@ -96,8 +94,6 @@ srcdir = .
 _build-aux ?= build-aux
 _autoreconf ?= autoreconf -v
 
-include ./maint.mk
-
 ifeq ($(.DEFAULT_GOAL),abort-due-to-no-makefile)
 $(MAKECMDGOALS): abort-due-to-no-makefile
 endif

ci/build-check.sh

@@ -9,7 +9,6 @@ ${dn}/build.sh
 topdir=$(git rev-parse --show-toplevel)
 resultsdir=$(mktemp -d)
 make check
-make syntax-check  # TODO: do syntax-check under check
 # See comment below
 for x in test-suite.log config.log; do
     mv ${x} ${resultsdir}