Store it in the shader_desc, and declare temps from that when compiling SPIR-V,
instead of parsing dcl_instructions.
As part of this change, we declare a single, global temps array (with Private
scope instead of Function) which is as large as the maximum of all dcl_temps
instructions. It is not clear to me whether this will improve, hurt, or have no
significant effect on the lower-level compiler. An alternative is to still
redeclare a new temps array every time (although still with a smaller size).
A struct declaration with variables is now absorbed into the 'declaration'
rule, like any other variable declaration.
A struct declaration without variables is now reduced to the
'struct_declaration_without_vars' rule.
They both are reduced to a 'declaration_statement' in the end.
In a declaration with multiple variables, the variables must be created
before the initializer of the next variable is parsed. This is required
for initializers such as:
float a = 1, b = a, c = b + 1;
A requisite for this is that the type information is parsed in the same
rule as the first variable (as a variable_def_typed) so it is
immediately available to declare the first variable. Then, the next
untyped variable declaration is parsed, and the type from the first
variable can be used to declare the second, before the third is parsed,
and so on.
