Fix clippy::useless_transmute

Author: tesuji

src/cli/self_update.rs

@@ -442,8 +442,6 @@ fn do_pre_install_options_sanity_checks(opts: &InstallOpts) -> Result<()> {
 fn do_anti_sudo_check(no_prompt: bool) -> Result<()> {
     #[cfg(unix)]
     pub fn home_mismatch() -> bool {
-        use libc as c;
-
         use std::env;
         use std::ffi::CStr;
         use std::mem;
@@ -460,13 +458,13 @@ fn do_anti_sudo_check(no_prompt: bool) -> Result<()> {
             return false;
         }
         let mut buf = [0u8; 1024];
-        let mut pwd = unsafe { mem::uninitialized::<c::passwd>() };
-        let mut pwdp: *mut c::passwd = ptr::null_mut();
+        let mut pwd = unsafe { mem::uninitialized::<libc::passwd>() };
+        let mut pwdp: *mut libc::passwd = ptr::null_mut();
         let rv = unsafe {
-            c::getpwuid_r(
-                c::geteuid(),
+            libc::getpwuid_r(
+                libc::geteuid(),
                 &mut pwd,
-                mem::transmute(&mut buf),
+                &mut buf as *mut [u8] as *mut i8,
                 buf.len(),
                 &mut pwdp,
             )