fix(webui): improve compatibility and memory handling

- replace deprecated std.posix.exit with std.process.exit in build script
- use std.mem.span to convert C string to Zig slice in getLastError
- fix memcpy to cast src pointer as mutable for FFI compatibility

Author: jinzhongjia

build.zig

@@ -43,7 +43,7 @@ pub fn build(b: *Build) !void {
         log.info("enable TLS support", .{});
         if (!target.query.isNative()) {
             log.info("when enable tls, not support cross compile", .{});
-            std.posix.exit(1);
+            std.process.exit(1);
         }
     }
 

src/webui.zig

@@ -57,7 +57,7 @@ pub const WebUIErrorInfo = struct {
 pub fn getLastError() WebUIErrorInfo {
     return .{
         .num = c.webui_get_last_error_number(),
-        .msg = c.webui_get_last_error_message(),
+        .msg = std.mem.span(c.webui_get_last_error_message()),
     };
 }
 
@@ -350,7 +350,7 @@ pub fn malloc(size: usize) ![]u8 {
 /// Copy raw data
 /// In general, you should not use this function
 pub fn memcpy(dst: []u8, src: []const u8) void {
-    c.webui_memcpy(@ptrCast(dst.ptr), @ptrCast(src.ptr), src.len);
+    c.webui_memcpy(@ptrCast(dst.ptr), @ptrCast(@constCast(src.ptr)), src.len);
 }
 
 /// Safely send raw data to the UI. All clients.