diff --git a/pkgs/by-name/pd/pdnsd/package.nix b/pkgs/by-name/pd/pdnsd/package.nix
index 34d4c93f8272..ab2f7690280d 100644
--- a/pkgs/by-name/pd/pdnsd/package.nix
+++ b/pkgs/by-name/pd/pdnsd/package.nix
@@ -29,7 +29,7 @@ stdenv.mkDerivation (finalAttrs: {
   configureFlags = [ "--enable-ipv6" ];
 
   # fix ipv6 on darwin
-  CPPFLAGS = "-D__APPLE_USE_RFC_3542";
+  env.CPPFLAGS = "-D__APPLE_USE_RFC_3542";
 
   meta = {
     description = "Permanent DNS caching";
diff --git a/pkgs/by-name/pg/pgadmin4/package.nix b/pkgs/by-name/pg/pgadmin4/package.nix
index 91b26eb89a3e..21ce2e8285fe 100644
--- a/pkgs/by-name/pg/pgadmin4/package.nix
+++ b/pkgs/by-name/pg/pgadmin4/package.nix
@@ -58,7 +58,7 @@ pythonPackages.buildPythonApplication rec {
   };
 
   # from Dockerfile
-  CPPFLAGS = "-DPNG_ARM_NEON_OPT=0";
+  env.CPPFLAGS = "-DPNG_ARM_NEON_OPT=0";
 
   format = "setuptools";
 
diff --git a/pkgs/by-name/rk/rkdeveloptool/package.nix b/pkgs/by-name/rk/rkdeveloptool/package.nix
index 2439b6136eb3..1799adfc7b29 100644
--- a/pkgs/by-name/rk/rkdeveloptool/package.nix
+++ b/pkgs/by-name/rk/rkdeveloptool/package.nix
@@ -26,9 +26,10 @@ stdenv.mkDerivation {
   buildInputs = [ libusb1 ];
 
   # main.cpp:1568:36: error: '%s' directive output may be truncated writing up to 557 bytes into a region of size 5
-  CPPFLAGS =
+  env.CPPFLAGS = toString (
     lib.optionals stdenv.cc.isGNU [ "-Wno-error=format-truncation" ]
-    ++ lib.optionals stdenv.isDarwin [ "-Wno-error=vla-cxx-extension" ];
+    ++ lib.optionals stdenv.isDarwin [ "-Wno-error=vla-cxx-extension" ]
+  );
 
   meta = {
     homepage = "https://github.com/rockchip-linux/rkdeveloptool";
diff --git a/pkgs/by-name/so/sooperlooper/package.nix b/pkgs/by-name/so/sooperlooper/package.nix
index c849da803959..0644d475067a 100644
--- a/pkgs/by-name/so/sooperlooper/package.nix
+++ b/pkgs/by-name/so/sooperlooper/package.nix
@@ -59,7 +59,7 @@ stdenv.mkDerivation (finalAttrs: {
   ];
 
   # see https://bugs.gentoo.org/925275
-  CPPFLAGS = "-fpermissive";
+  env.CPPFLAGS = "-fpermissive";
 
   enableParallelBuilding = true;