Update LIBBPF_SYS_LIBRARY_PATH_<TARGET> in documentation to LIBBPF_SYS_LIBRARY_PATH_<TARGET_TRIPLE> to help clarify the intended usage.

Update paths in `LIBBPF_SYS_LIBRARY_PATH_<TARGET_TRIPLE>` to take precedence over ones in `LIBBPF_SYS_LIBRARY_PATH`

Author: amirbou

README.md

@@ -41,7 +41,7 @@ $ cargo build
 
 - `LIBBPF_SYS_EXTRA_CFLAGS` can be used to pass extra cflags when vendoring libbpf, libz or libelf.
 - `LIBBPF_SYS_LIBRARY_PATH`: colon separated paths for the linker to find native libs.
-- `LIBBPF_SYS_LIBRARY_PATH_<TARGET>`: similar to `LIBBPF_SYS_LIBRARY_PATH`, but used to set per-target library path, to help cross-compilation environments. If `LIBBPF_SYS_LIBRARY_PATH_<TARGET>` and `LIBBPF_SYS_LIBRARY_PATH` are defined, the paths from both will be used.
+- `LIBBPF_SYS_LIBRARY_PATH_<TARGET_TRIPLE>`: similar to `LIBBPF_SYS_LIBRARY_PATH`, but used to set per-target library path, to help cross-compilation environments. If `LIBBPF_SYS_LIBRARY_PATH_<TARGET_TRIPLE>` and `LIBBPF_SYS_LIBRARY_PATH` are defined, the paths from both will be used, and the "target" paths will have precedence.
 
 ### Distribution
 

build.rs

@@ -216,9 +216,9 @@ fn main() {
     println!("cargo:rerun-if-env-changed={}", target_lib_path_underscored);
 
     let lib_paths = vec![
-        env::var(global_lib_path),
         env::var(target_lib_path),
         env::var(target_lib_path_underscored),
+        env::var(global_lib_path),
     ];
 
     for lib_path in lib_paths {
@@ -246,7 +246,7 @@ fn open_lockable(path: &Path) -> io::Result<File> {
             // with write permissions. So just open for reading and hope
             // for the best.
             File::open(path)
-        },
+        }
         e @ Err(..) => e,
     }
 }