diff --git a/pkgs/development/libraries/libunwind/default.nix b/pkgs/development/libraries/libunwind/default.nix
index 3816788f929..7e481034f43 100644
--- a/pkgs/development/libraries/libunwind/default.nix
+++ b/pkgs/development/libraries/libunwind/default.nix
@@ -21,7 +21,7 @@ stdenv.mkDerivation rec {
 
   # Without latex2man, no man pages are installed despite being
   # prebuilt in the source tarball.
-  configureFlags = "LATEX2MAN=${coreutils}/bin/true";
+  configureFlags = [ "LATEX2MAN=${coreutils}/bin/true" ];
 
   propagatedBuildInputs = [ xz ];
 
diff --git a/pkgs/development/tools/misc/strace/default.nix b/pkgs/development/tools/misc/strace/default.nix
index 6b797481799..877aedc4e49 100644
--- a/pkgs/development/tools/misc/strace/default.nix
+++ b/pkgs/development/tools/misc/strace/default.nix
@@ -16,7 +16,7 @@ stdenv.mkDerivation rec {
 
   postPatch = "patchShebangs --host strace-graph";
 
-  configureFlags = stdenv.lib.optional (!stdenv.hostPlatform.isx86) "--enable-mpers=check";
+  configureFlags = [ "--enable-mpers=check" ];
 
   meta = with stdenv.lib; {
     homepage = "https://strace.io/";
diff --git a/pkgs/top-level/php-packages.nix b/pkgs/top-level/php-packages.nix
index 95b6d96644d..cb3cfdf7651 100644
--- a/pkgs/top-level/php-packages.nix
+++ b/pkgs/top-level/php-packages.nix
@@ -310,7 +310,7 @@ lib.makeScope pkgs.newScope (self: with self; {
           })
         ];
         postPhpize = ''substituteInPlace configure --replace 'as_fn_error $? "Cannot locate header file libintl.h" "$LINENO" 5' ':' '';
-        configureFlags = "--with-gettext=${gettext}"; }
+        configureFlags = [ "--with-gettext=${gettext}" ]; }
       { name = "gmp";
         buildInputs = [ gmp ];
         configureFlags = [ "--with-gmp=${gmp.dev}" ]; }