[orm] C error while field default value include ""

[kbkpbot]

Describe the bug

When create a field with default value include "" in it, it will generate a C error.

Reproduction Steps

o.v

module main

import db.mysql


fn main() {
        db := db_mysql() or { panic('failed to connect to database') }

        sql db {
                create table User
        } or { panic(err) }
}

@[table: 'sys_users']
struct User {
pub:
        home_path ?string @[default: '"dashboard"'; sql_type: 'VARCHAR(64)']   // "dashboard" will compile fail.
}

fn db_mysql() !mysql.DB {

        mut mysql_config := mysql.Config{
                host:     '127.0.0.1'
                port:     3306
                username: 'root'
                password: '12345678'
                dbname:   'vcore'
        }

        mut conn := mysql.connect(mysql_config) or {
                return err
        }

        return conn
}

v o.v

Expected Behavior

compile ok

Current Behavior

$ v o.v
================== C compilation error (from tcc): ==============
cc: /tmp/v_1000/o.01JQ9CGNBWZD724RNJ8FXMAJF7.tmp.c:10572: warning: assignment discards qualifiers from pointer target type
cc: /tmp/v_1000/o.01JQ9CGNBWZD724RNJ8FXMAJF7.tmp.c:10612: error: ')' expected (got "dashboard")
...
cc: /tmp/v_1000/o.01JQ9CGNBWZD724RNJ8FXMAJF7.tmp.c:10612: error: ')' expected (got "dashboard")
(note: the original output was 4 lines long; it was truncated to its first 2 lines + the last line)
=================================================================
(You can pass `-cg`, or `-show-c-output` as well, to print all the C error messages).
builder error:
==================
C error found. It should never happen, when compiling pure V code.
This is a V compiler bug, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.10 bd2ec67.f7f89b3

Environment details (OS name and version, etc.)

V full version	V 0.4.10 bd2ec67.f7f89b3
OS	linux, Ubuntu 24.04.2 LTS
Processor	8 cpus, 64bit, little endian, Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz
Memory	10.83GB/15.51GB
V executable	/media/HD/github/kbkpbot/v/v
V last modified time	2025-03-26 13:08:17
V home dir	OK, value: /media/HD/github/kbkpbot/v
VMODULES	OK, value: /home/mars/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/mars/v/bug/orm
Git version	git version 2.43.0
V git status	weekly.2025.13-14-gf7f89b3c-dirty (2 commit(s) behind V master)
.git/config present	true
cc version	cc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
gcc version	gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
clang version	Ubuntu clang version 18.1.3 (1ubuntu1)
tcc version	tcc version 0.9.28rc 2024-07-31 HEAD@1cee0908 (x86_64 Linux)
tcc git status	thirdparty-linux-amd64 0134e9b9-dirty
emcc version	N/A
glibc version	ldd (Ubuntu GLIBC 2.39-0ubuntu8.4) 2.39

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