param: Introduce the notion of simple parameters

The simple parameters are those that successfully migrated to params.h
because they were trivial to declare in a way that could be used in all
the places where they are needed.

The PARAM() macro is now changed so that the outstanding `type` argument
is separated from arguments matching struct parspec fields. To minimize
disruption the new PARAM_SIMPLE() macro takes parameters in the order of
the previous PARAM() definition.

Refs #3250

bin/varnishd/common/common_param.h

@@ -82,7 +82,7 @@ struct params {
 #define	ptyp_uint	unsigned
 #define	ptyp_vsl_buffer	unsigned
 #define	ptyp_vsl_reclen	unsigned
-#define PARAM(nm, ty, ...)		\
+#define PARAM(ty, nm, ...)		\
 	ptyp_##ty		nm;
 #include <tbl/params.h>
 #undef ptyp_bool

bin/varnishd/mgt/mgt_param_tbl.c

@@ -39,7 +39,7 @@
 
 
 struct parspec mgt_parspec[] = {
-#define PARAM(nm, ty, ...) { #nm, tweak_##ty, &mgt_param.nm, __VA_ARGS__ },
+#define PARAM(ty, nm, ...) { #nm, __VA_ARGS__ },
 #include "tbl/params.h"
 
 	{ "cc_command", tweak_string, &mgt_cc_cmd,