mailcore2: fix build on darwin

pkgs/development/libraries/mailcore2/default.nix

@@ -1,5 +1,6 @@
 { stdenv, lib, fetchFromGitHub, cmake, libetpan, icu, cyrus_sasl, libctemplate
 , libuchardet, pkg-config, glib, html-tidy, libxml2, libuuid, openssl
+, darwin
 }:
 
 stdenv.mkDerivation rec {
@@ -16,8 +17,14 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ cmake pkg-config ];
   buildInputs = [
-    libetpan icu cyrus_sasl libctemplate libuchardet glib
+    libetpan cyrus_sasl libctemplate libuchardet
-    html-tidy libxml2 libuuid openssl
+    html-tidy libxml2 openssl
+  ] ++ lib.optionals stdenv.isLinux [
+    glib
+    icu
+    libuuid
+  ] ++ lib.optionals stdenv.isDarwin [
+    darwin.apple_sdk.frameworks.Foundation
   ];
 
   postPatch = ''
@@ -28,13 +35,14 @@ stdenv.mkDerivation rec {
        --replace "/usr/include/libxml2" "${libxml2.dev}/include/libxml2"
     substituteInPlace src/core/basetypes/MCHTMLCleaner.cpp \
       --replace buffio.h tidybuffio.h
-    substituteInPlace src/core/basetypes/MCICUTypes.h \
-      --replace "__CHAR16_TYPE__ UChar" "char16_t UChar"
     substituteInPlace src/core/basetypes/MCString.cpp \
       --replace "xmlErrorPtr" "const xmlError *"
+  '' + lib.optionalString (!stdenv.isDarwin) ''
+    substituteInPlace src/core/basetypes/MCICUTypes.h \
+      --replace "__CHAR16_TYPE__ UChar" "char16_t UChar"
   '';
 
-  cmakeFlags = [
+  cmakeFlags = lib.optionals (!stdenv.isDarwin) [
     "-DBUILD_SHARED_LIBS=ON"
   ];
 
@@ -43,10 +51,10 @@ stdenv.mkDerivation rec {
     cp -r src/include $out
 
     mkdir $out/lib
-    cp src/libMailCore.so $out/lib
+    cp src/libMailCore.* $out/lib
   '';
 
-  doCheck = true;
+  doCheck = !stdenv.isDarwin;
   checkPhase = ''
     (
       cd unittest
@@ -59,5 +67,6 @@ stdenv.mkDerivation rec {
     homepage    = "http://libmailcore.com";
     license     = licenses.bsd3;
     maintainers = with maintainers; [ ];
+    platforms   = platforms.unix;
   };
 }