Apply suggestions from code review

Co-authored-by: Alan Somers <asomers@gmail.com>

Author: folkertdev

src/unix/bsd/freebsdlike/freebsd/freebsd11/mod.rs

@@ -428,6 +428,7 @@ extern "C" {
     // Argument order of the function pointer changed in FreeBSD 14. From 14 onwards the signature
     // matches the POSIX specification by having the third argument be a mutable pointer, on
     // earlier versions the first argument is the mutable pointer.
+    #[link_name = "qsort_r@FBSD_1.0"]
     pub fn qsort_r(
         base: *mut c_void,
         num: size_t,

src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs

@@ -469,6 +469,7 @@ extern "C" {
     pub fn dirname(path: *mut c_char) -> *mut c_char;
     pub fn basename(path: *mut c_char) -> *mut c_char;
 
+    #[link_name = "qsort_r@FBSD_1.0"]
     pub fn qsort_r(
         base: *mut c_void,
         num: size_t,

src/unix/bsd/freebsdlike/freebsd/freebsd13/mod.rs

@@ -508,6 +508,7 @@ extern "C" {
     pub fn dirname(path: *mut c_char) -> *mut c_char;
     pub fn basename(path: *mut c_char) -> *mut c_char;
 
+    #[link_name = "qsort_r@FBSD_1.0"]
     pub fn qsort_r(
         base: *mut c_void,
         num: size_t,