all: fix CI issues with auto-deref vars, sha512 stack alloc, and Vinix build

Author: medvednikov

vlib/crypto/sha512/sha512block_generic.v

@@ -38,7 +38,7 @@ const _k = [
 fn block_generic(mut dig Digest, p_ []u8) {
 	unsafe {
 		mut p := p_
-		mut w := []u64{len: (80)}
+		mut w := [80]u64{}
 		mut h0 := dig.h[0]
 		mut h1 := dig.h[1]
 		mut h2 := dig.h[2]

vlib/v/checker/checker.v

@@ -6514,6 +6514,9 @@ fn (mut c Checker) prefix_expr(mut node ast.PrefixExpr) ast.Type {
 		if right_type.is_ptr() {
 			return right_type.deref()
 		}
+		if expr.is_auto_deref_var() {
+			return right_type
+		}
 		if !right_type.is_pointer() && !c.pref.translated && !c.file.is_translated {
 			s := c.table.type_to_str(right_type)
 			c.error('invalid indirect of `${s}`, the type `${right_sym.name}` is not a pointer',

vlib/v/gen/c/assign.v

@@ -1107,7 +1107,11 @@ fn (mut g Gen) assign_stmt(node_ ast.AssignStmt) {
 				if left_sym.kind == .function {
 					g.write('{void* _ = ')
 				} else {
-					g.write('{${styp} _ = ')
+					mut actual_styp := styp
+					if val is ast.Ident && val.is_auto_deref_var() {
+						actual_styp = '${styp}*'
+					}
+					g.write('{${actual_styp} _ = ')
 				}
 				if (val in [ast.MatchExpr, ast.IfExpr, ast.ComptimeSelector] || is_fixed_array_var)
 					&& unaliased_right_sym.info is ast.ArrayFixed {