use core::os::consts instead of hard coded contant value

Author: ILyoan

src/librustc/metadata/loader.rs

@@ -18,6 +18,7 @@ use lib::llvm::{False, llvm, mk_object_file, mk_section_iter};
 use metadata::filesearch::FileSearch;
 use io::WriterUtil;
 use syntax::parse::token::ident_interner;
+use core::os::consts::{macos, freebsd, linux, win32};
 
 export os;
 export os_macos, os_win32, os_linux, os_freebsd;
@@ -67,10 +68,14 @@ fn find_library_crate(cx: ctxt) -> Option<{ident: ~str, data: @~[u8]}> {
 fn libname(cx: ctxt) -> {prefix: ~str, suffix: ~str} {
     if cx.static { return {prefix: ~"lib", suffix: ~".rlib"}; }
     match cx.os {
-      os_win32 => return {prefix: ~"", suffix: ~".dll"},
-      os_macos => return {prefix: ~"lib", suffix: ~".dylib"},
-      os_linux => return {prefix: ~"lib", suffix: ~".so"},
-      os_freebsd => return {prefix: ~"lib", suffix: ~".so"}
+      os_win32 => return {prefix: win32::dll_prefix(), 
+                          suffix: win32::dll_suffix()},
+      os_macos => return {prefix: macos::dll_prefix(),
+                          suffix: macos::dll_suffix()},
+      os_linux => return {prefix: linux::dll_prefix(), 
+                          suffix: linux::dll_suffix()},
+      os_freebsd => return {prefix: freebsd::dll_prefix(), 
+                            suffix: freebsd::dll_suffix()}
     }
 }