Add support for FreeBSD CURRENT (aka freebsd13)

Currently, libc supports and detects freebsd11 and freebsd13
Unknown versions, like freebsd13, is treated as freebsd11.
This patch solve the issues, detecting freebsd13 and treating it like
freebsd12.
Inverting the logic not(freebsd12) -> freebsd11 where possible

1 files changed, 4 insertions, 0 deletions

diff --git a/build.rs b/build.rs
index 76ca0961e4..c43cca36d2 100644
--- a/build.rs
+++ b/build.rs
@@ -19,6 +19,9 @@ fn main() {
         if let Some(12) = which_freebsd() {
             println!("cargo:rustc-cfg=freebsd12");
         }
+        if let Some(13) = which_freebsd() {
+            println!("cargo:rustc-cfg=freebsd13");
+        }
     }
 
     // Rust >= 1.15 supports private module use:
@@ -100,6 +103,7 @@ fn which_freebsd() -> Option<i32> {
     match &stdout {
         s if s.starts_with("11") => Some(11),
         s if s.starts_with("12") => Some(12),
+        s if s.starts_with("13") => Some(13),
         _ => None,
     }
 }