subversion: fix darwin

pkgs/applications/version-management/subversion/default.nix

@@ -49,6 +49,14 @@ let
     # "-P" CPPFLAG is needed to build Python bindings and subversionClient
     CPPFLAGS = [ "-P" ];
 
+    env = lib.optionalAttrs stdenv.cc.isClang {
+      NIX_CFLAGS_COMPILE = lib.concatStringsSep " " [
+        "-Wno-error=implicit-function-declaration"
+        "-Wno-error=implicit-int"
+        "-Wno-int-conversion"
+      ];
+    };
+
     preConfigure = lib.optionalString needsAutogen ''
       ./autogen.sh
     '';