Provide a functional workaround for crashing bash on inital build

modules/environment/login/login.nix

@@ -1,23 +1,45 @@
 # Licensed under GNU Lesser General Public License v3 or later, see COPYING.
 # Copyright (c) 2019 Alexander Sosedkin and other contributors, see AUTHORS.
 
-{ config, writeScript }:
+{ config, lib, writeScript }:
+
+let
+  inherit (config.build) installationDir;
+in
 
 writeScript "login" ''
   #!/system/bin/sh
   set -e
 
   export USER="${config.user.userName}"
-  export PROOT_TMP_DIR=${config.build.installationDir}/tmp
-  export PROOT_L2S_DIR=${config.build.installationDir}/.l2s
+  export PROOT_TMP_DIR=${installationDir}/tmp
+  export PROOT_L2S_DIR=${installationDir}/.l2s
 
-  exec "${config.build.installationDir}/bin/proot-static" \
-    -b ${config.build.installationDir}/nix:/nix \
-    -b ${config.build.installationDir}/bin:/bin \
-    -b ${config.build.installationDir}/etc:/etc \
-    -b ${config.build.installationDir}/tmp:/tmp \
-    -b ${config.build.installationDir}/usr:/usr \
-    -b /:/android \
-    --link2symlink \
-    ${config.build.installationDir}/bin/sh ${config.build.installationDir}/usr/lib/login-inner "$@"
+  ${
+    if config.build.initialBuild
+    then ''
+      ${installationDir}/bin/proot-static \
+        -b ${installationDir}/nix:/nix \
+        -b ${installationDir}/bin:/bin \
+        -b ${installationDir}/etc:/etc \
+        -b ${installationDir}/tmp:/tmp \
+        -b ${installationDir}/usr:/usr \
+        -b /:/android \
+        --link2symlink \
+        ${installationDir}/bin/sh ${installationDir}/usr/lib/login-inner "$@"
+
+      exec ${installationDir}/bin/login "$@"
+    ''
+    else ''
+      exec ${installationDir}/bin/proot-static \
+        -b ${installationDir}/nix:/nix \
+        -b ${installationDir}/bin:/bin \
+        -b ${installationDir}/etc:/etc \
+        -b ${installationDir}/tmp:/tmp \
+        -b ${installationDir}/usr:/usr \
+        -b /:/android \
+        --link2symlink \
+        ${installationDir}/bin/sh ${installationDir}/usr/lib/login-inner "$@"
+    ''
+  }
 ''