php: Make buildEnv recursive + take extension deps into account

A slight rewrite of buildEnv which:

1. Makes buildEnv recursively add itself to its output, so that it can
   be accessed from any php derivation.

2. Orders the extension text strings according to their internalDeps
   attribute - dependencies have to be put before dependants in the
   php.ini or they will fail to load due to missing symbols.

pkgs/development/interpreters/php/default.nix

@@ -144,20 +144,45 @@ let
     };
   };
 
-  generic' = { version, sha256, ... }@args: let php = generic args; in php.overrideAttrs (_: {
-    passthru.buildEnv = { exts ? (_: []), extraConfig ? "" }: let
+  generic' = { version, sha256, ... }@args:
+    let
+      php = generic args;
+      buildEnv = { exts ? (_: []), extraConfig ? "" }:
+        let
+          getExtName = ext: lib.removePrefix "php-" (builtins.parseDrvName ext.name).name;
+          extList = exts (callPackage ../../../top-level/php-packages.nix { inherit php; });
+
+          # Generate extension load configuration snippets from
+          # exts. This is an attrset suitable for use with
+          # textClosureList, which is used to put the strings in the
+          # right order - if a plugin which is dependent on another
+          # plugin is placed before its dependency, it will fail to
+          # load.
+          extensionTexts =
+            lib.listToAttrs
+              (map (ext:
+                let
+                  extName = getExtName ext;
+                  type = "${lib.optionalString (ext.zendExtension or false) "zend_"}extension";
+                in
+                  lib.nameValuePair extName {
+                    text = "${type}=${ext}/lib/php/extensions/${extName}.so";
+                    deps = lib.optionals (ext ? internalDeps) ext.internalDeps;
+                  })
+                extList);
+
+          extNames = map getExtName extList;
           extraInit = writeText "custom-php.ini" ''
             ${extraConfig}
-        ${lib.concatMapStringsSep "\n" (ext: let
-          extName = lib.removePrefix "php-" (builtins.parseDrvName ext.name).name;
-          type = "${lib.optionalString (ext.zendExtension or false) "zend_"}extension";
-        in ''
-          ${type}=${ext}/lib/php/extensions/${extName}.so
-        '') (exts (callPackage ../../../top-level/php-packages.nix { inherit php; }))}
+            ${lib.concatStringsSep "\n"
+              (lib.textClosureList extensionTexts extNames)}
           '';
-    in symlinkJoin {
-      name = "php-custom-${version}";
+        in
+          symlinkJoin {
+            name = "php-with-extensions-${version}";
+            inherit version;
             nativeBuildInputs = [ makeWrapper ];
+            passthru.buildEnv = buildEnv;
             paths = [ php ];
             postBuild = ''
               wrapProgram $out/bin/php \
@@ -166,6 +191,9 @@ let
                 --add-flags "-c ${extraInit}"
             '';
           };
+    in
+      php.overrideAttrs (_: {
+        passthru.buildEnv = buildEnv;
       });
 
   php72base = generic' {

pkgs/top-level/php-packages.nix

@@ -717,7 +717,7 @@ let
       , doCheck ? true
       , ...
     }: stdenv.mkDerivation {
-      pname = "php-ext-${name}";
+      pname = "php-${name}";
 
       inherit (php) version src;
       sourceRoot = "php-${php.version}/ext/${name}";
@@ -746,7 +746,7 @@ let
       checkPhase = "echo n | make test";
       installPhase = ''
         mkdir -p $out/lib/php/extensions
-        cp modules/${name}.so $out/lib/php/extensions/ext-${name}.so
+        cp modules/${name}.so $out/lib/php/extensions/${name}.so
       '';
     };