remove function struct export workaround for arch_x64_user header

src/header/arch_x64_user/cbindgen.toml

@@ -5,3 +5,13 @@ style = "Tag"
 
 [enum]
 prefix_with_name = true
+
+[export]
+include = [
+  "user_fpregs_struct",
+  "user_regs_struct",
+  "user",
+  "elf_gregset_t",
+  "elf_greg_t",
+  "elf_fpregset_t"
+]

src/header/arch_x64_user/mod.rs

@@ -70,14 +70,3 @@ pub struct user {
     pub u_comm: [c_char; 32],
     pub u_debugreg: [c_ulong; 8],
 }
-
-#[unsafe(no_mangle)]
-pub extern "C" fn _cbindgen_export_x86_user(
-    a: user_fpregs_struct,
-    b: user_regs_struct,
-    c: user,
-    d: elf_gregset_t,
-    e: elf_greg_t,
-    f: elf_fpregset_t,
-) {
-}