xml-security-c: fix gcc6 build

pkgs/development/libraries/xml-security-c/cxx11.patch

@@ -0,0 +1,11 @@
+--- xml-security-c-1.6.1/xsec/tools/checksig/InteropResolver.cpp.orig	2016-02-02 23:57:26.204655144 +0000
++++ xml-security-c-1.6.1/xsec/tools/checksig/InteropResolver.cpp	2016-02-02 23:57:35.796692305 +0000
+@@ -645,7 +645,7 @@
+ 
+ 	}
+ 
+-	return false;
++	return NULL;
+ 
+ }
+ 

pkgs/development/libraries/xml-security-c/default.nix

@@ -9,18 +9,19 @@ stdenv.mkDerivation rec {
     sha256 = "e5226e7319d44f6fd9147a13fb853f5c711b9e75bf60ec273a0ef8a190592583";
   };
 
-  patchPhase = ''
+  patches = [ ./cxx11.patch ];
+
+  postPatch = ''
     mkdir -p xsec/yes/lib
     sed -i -e 's/-O2 -DNDEBUG/-DNDEBUG/g' configure
   '';
 
-  configurePhase = ''
-    ./configure --prefix=$out \
-                --with-openssl \
-                --with-xerces \
-                --with-xalan \
-                --disable-static
-  '';
+  configureFlags = [
+    "--with-openssl"
+    "--with-xerces"
+    "--with-xalan"
+    "--disable-static"
+  ];
 
   buildInputs = [ xalanc xercesc openssl pkgconfig ];