Fix license attribute of many bsd-like licensed packages

pkgs/development/compilers/chicken/default.nix

@@ -61,7 +61,7 @@ stdenv.mkDerivation {
 
   meta = {
     homepage = http://www.call-cc.org/;
-    license = "BSD";
+    license = stdenv.lib.licenses.bsd3;
     maintainers = with stdenv.lib.maintainers; [ the-kenny ];
     platforms = with stdenv.lib.platforms; allBut darwin;
     description = "A portable compiler for the Scheme programming language";

pkgs/development/compilers/edk2/default.nix

@@ -33,8 +33,8 @@ edk2 = stdenv.mkDerivation {
 
   meta = {
     description = "Intel EFI development kit";
-    homepage = http://sourceforge.net/apps/mediawiki/tianocore/index.php?title=EDK2;
-    license = "BSD";
+    homepage = http://sourceforge.net/projects/edk2/;
+    license = stdenv.lib.licenses.bsd2;
     maintainers = [ stdenv.lib.maintainers.shlevy ];
     platforms = ["x86_64-linux" "i686-linux"];
   };

pkgs/development/compilers/yasm/default.nix

@@ -8,10 +8,10 @@ stdenv.mkDerivation rec {
     sha256 = "0gv0slmm0qpq91za3v2v9glff3il594x5xsrbgab7xcmnh0ndkix";
   };
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = http://www.tortall.net/projects/yasm/;
     description = "Complete rewrite of the NASM assembler";
-    license = "BSD";
-    platforms = stdenv.lib.platforms.unix;
+    license = licenses.bsd2;
+    platforms = platforms.unix;
   };
 }