build: Don't involve C flags to include config.h

Spotted this unusual construct while sweeping through the sanitizer flags.

bin/varnishd/Makefile.am

@@ -180,17 +180,16 @@ endif
 
 noinst_PROGRAMS = vhp_gen_hufdec
 vhp_gen_hufdec_SOURCES = hpack/vhp_gen_hufdec.c
-vhp_gen_hufdec_CFLAGS = -include config.h
 vhp_gen_hufdec_LDADD = $(top_builddir)/lib/libvarnish/libvarnish.la
 
 noinst_PROGRAMS += vhp_table_test
 vhp_table_test_SOURCES = hpack/vhp_table.c
-vhp_table_test_CFLAGS = -DTABLE_TEST_DRIVER -include config.h
+vhp_table_test_CFLAGS = -DTABLE_TEST_DRIVER
 vhp_table_test_LDADD = $(top_builddir)/lib/libvarnish/libvarnish.la
 
 noinst_PROGRAMS += vhp_decode_test
 vhp_decode_test_SOURCES = hpack/vhp_decode.c hpack/vhp_table.c
-vhp_decode_test_CFLAGS = -DDECODE_TEST_DRIVER -include config.h
+vhp_decode_test_CFLAGS = -DDECODE_TEST_DRIVER
 vhp_decode_test_LDADD = $(top_builddir)/lib/libvarnish/libvarnish.la
 
 noinst_PROGRAMS += esi_parse_fuzzer
@@ -198,7 +197,7 @@ esi_parse_fuzzer_SOURCES = \
 	cache/cache_esi_parse.c \
 	fuzzers/esi_parse_fuzzer.c
 esi_parse_fuzzer_CFLAGS = \
-	-DNOT_IN_A_VMOD -DTEST_DRIVER -include config.h
+	-DNOT_IN_A_VMOD -DTEST_DRIVER
 esi_parse_fuzzer_LDADD = \
 	$(top_builddir)/lib/libvarnish/libvarnish.la \
 	$(top_builddir)/lib/libvgz/libvgz.a

bin/varnishd/fuzzers/esi_parse_fuzzer.c

@@ -30,6 +30,8 @@
  * ESI parser fuzzer.
  */
 
+#include "config.h"
+
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>

bin/varnishd/hpack/vhp_gen_hufdec.c

@@ -28,6 +28,8 @@
  * SUCH DAMAGE.
  */
 
+#include "config.h"
+
 #include <stdlib.h>
 #include <ctype.h>
 #include <stdint.h>