diff --git a/src/libstore-tests/meson.build b/src/libstore-tests/meson.build
index 1822a3520..8a1ff40f0 100644
--- a/src/libstore-tests/meson.build
+++ b/src/libstore-tests/meson.build
@@ -40,6 +40,8 @@ deps_private += gtest
 configdata = configuration_data()
 configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
 
+configdata.set_quoted('NIX_STORE_DIR', nix_store.get_variable('storedir'))
+
 config_priv_h = configure_file(
   configuration : configdata,
   output : 'store-tests-config.hh',
@@ -89,7 +91,6 @@ this_exe = executable(
   include_directories : include_dirs,
   # TODO: -lrapidcheck, see ../libutil-support/build.meson
   link_args: linker_export_flags + ['-lrapidcheck'],
-  cpp_args : [ '-DNIX_STORE_DIR="' + nix_store.get_variable('storedir') + '"' ],
   # get main from gtest
   install : true,
 )
diff --git a/src/libstore/meson.build b/src/libstore/meson.build
index 59c62fe04..ae50686b6 100644
--- a/src/libstore/meson.build
+++ b/src/libstore/meson.build
@@ -154,12 +154,14 @@ endforeach
 
 busybox = find_program(get_option('sandbox-shell'), required : false)
 
-# This one goes in config.h
-# The path to busybox is passed as a -D flag when compiling this_library.
-# This solution is inherited from the old make buildsystem
-# TODO: do this differently?
 configdata_priv.set('HAVE_EMBEDDED_SANDBOX_SHELL', get_option('embedded-sandbox-shell').to_int())
 
+if get_option('embedded-sandbox-shell')
+  configdata_priv.set_quoted('SANDBOX_SHELL', '__embedded_sandbox_shell__')
+elif busybox.found()
+  configdata_priv.set_quoted('SANDBOX_SHELL', busybox.full_path())
+endif
+
 if get_option('embedded-sandbox-shell')
   hexdump = find_program('hexdump', native : true)
   embedded_sandbox_shell_gen = custom_target(
@@ -178,6 +180,66 @@ if get_option('embedded-sandbox-shell')
   generated_headers += embedded_sandbox_shell_gen
 endif
 
+fs = import('fs')
+
+prefix = get_option('prefix')
+# For each of these paths, assume that it is relative to the prefix unless
+# it is already an absolute path (which is the default for store-dir, localstatedir, and log-dir).
+path_opts = [
+  # Meson built-ins.
+  'datadir',
+  'mandir',
+  'libdir',
+  'includedir',
+  'libexecdir',
+  # Homecooked Nix directories.
+  'store-dir',
+  'localstatedir',
+  'log-dir',
+]
+# For your grepping pleasure, this loop sets the following variables that aren't mentioned
+# literally above:
+# store_dir
+# localstatedir
+# log_dir
+# profile_dir
+foreach optname : path_opts
+  varname = optname.replace('-', '_')
+  path = get_option(optname)
+  if fs.is_absolute(path)
+    set_variable(varname, path)
+  else
+    set_variable(varname, prefix / path)
+  endif
+endforeach
+
+# sysconfdir doesn't get anything installed to directly, and is only used to
+# tell Nix where to look for nix.conf, so it doesn't get appended to prefix.
+sysconfdir = get_option('sysconfdir')
+if not fs.is_absolute(sysconfdir)
+  sysconfdir = '/' / sysconfdir
+endif
+
+# Aside from prefix itself, each of these was made into an absolute path
+# by joining it with prefix, unless it was already an absolute path
+# (which is the default for store-dir, localstatedir, and log-dir).
+configdata_priv.set_quoted('NIX_PREFIX',    prefix)
+configdata_priv.set_quoted('NIX_STORE_DIR', store_dir)
+configdata_priv.set_quoted('NIX_DATA_DIR',  datadir)
+configdata_priv.set_quoted('NIX_STATE_DIR', localstatedir / 'nix')
+configdata_priv.set_quoted('NIX_LOG_DIR',   log_dir)
+configdata_priv.set_quoted('NIX_CONF_DIR',  sysconfdir / 'nix')
+configdata_priv.set_quoted('NIX_MAN_DIR',   mandir)
+
+lsof = find_program('lsof', required : false)
+configdata_priv.set_quoted(
+  'LSOF',
+  lsof.found()
+    ? lsof.full_path()
+    # Just look up on the PATH
+    : 'lsof',
+)
+
 config_priv_h = configure_file(
   configuration : configdata_priv,
   output : 'store-config-private.hh',
@@ -266,89 +328,6 @@ else
   subdir('unix')
 endif
 
-fs = import('fs')
-
-prefix = get_option('prefix')
-# For each of these paths, assume that it is relative to the prefix unless
-# it is already an absolute path (which is the default for store-dir, localstatedir, and log-dir).
-path_opts = [
-  # Meson built-ins.
-  'datadir',
-  'mandir',
-  'libdir',
-  'includedir',
-  'libexecdir',
-  # Homecooked Nix directories.
-  'store-dir',
-  'localstatedir',
-  'log-dir',
-]
-# For your grepping pleasure, this loop sets the following variables that aren't mentioned
-# literally above:
-# store_dir
-# localstatedir
-# log_dir
-# profile_dir
-foreach optname : path_opts
-  varname = optname.replace('-', '_')
-  path = get_option(optname)
-  if fs.is_absolute(path)
-    set_variable(varname, path)
-  else
-    set_variable(varname, prefix / path)
-  endif
-endforeach
-
-# sysconfdir doesn't get anything installed to directly, and is only used to
-# tell Nix where to look for nix.conf, so it doesn't get appended to prefix.
-sysconfdir = get_option('sysconfdir')
-if not fs.is_absolute(sysconfdir)
-  sysconfdir = '/' / sysconfdir
-endif
-
-lsof = find_program('lsof', required : false)
-
-# Aside from prefix itself, each of these was made into an absolute path
-# by joining it with prefix, unless it was already an absolute path
-# (which is the default for store-dir, localstatedir, and log-dir).
-cpp_str_defines = {
-  'NIX_PREFIX':    prefix,
-  'NIX_STORE_DIR': store_dir,
-  'NIX_DATA_DIR':  datadir,
-  'NIX_STATE_DIR': localstatedir / 'nix',
-  'NIX_LOG_DIR':   log_dir,
-  'NIX_CONF_DIR':  sysconfdir / 'nix',
-  'NIX_MAN_DIR':   mandir,
-}
-
-if lsof.found()
-  lsof_path = lsof.full_path()
-else
-  # Just look up on the PATH
-  lsof_path = 'lsof'
-endif
-cpp_str_defines += {
-  'LSOF': lsof_path
-}
-
-if get_option('embedded-sandbox-shell')
-  cpp_str_defines += {
-    'SANDBOX_SHELL': '__embedded_sandbox_shell__'
-  }
-elif busybox.found()
-  cpp_str_defines += {
-    'SANDBOX_SHELL': busybox.full_path()
-  }
-endif
-
-cpp_args = []
-
-foreach name, value : cpp_str_defines
-  cpp_args += [
-    '-D' + name + '=' + '"' + value + '"'
-  ]
-endforeach
-
 subdir('nix-meson-build-support/export-all-symbols')
 subdir('nix-meson-build-support/windows-version')
 
@@ -359,7 +338,6 @@ this_library = library(
   config_priv_h,
   dependencies : deps_public + deps_private + deps_other,
   include_directories : include_dirs,
-  cpp_args : cpp_args,
   link_args: linker_export_flags,
   prelink : true, # For C++ static initializers
   install : true,
diff --git a/src/nix/man-pages.cc b/src/nix/man-pages.cc
index 8da439e7b..8585c164c 100644
--- a/src/nix/man-pages.cc
+++ b/src/nix/man-pages.cc
@@ -1,4 +1,5 @@
 #include "man-pages.hh"
+#include "cli-config-private.hh"
 #include "nix/util/file-system.hh"
 #include "nix/util/current-process.hh"
 #include "nix/util/environment-variables.hh"
diff --git a/src/nix/meson.build b/src/nix/meson.build
index b258778cc..3cb45f1f5 100644
--- a/src/nix/meson.build
+++ b/src/nix/meson.build
@@ -39,13 +39,16 @@ configdata = configuration_data()
 configdata.set_quoted('NIX_CLI_VERSION', meson.project_version())
 
 fs = import('fs')
+prefix = get_option('prefix')
 
 bindir = get_option('bindir')
-if not fs.is_absolute(bindir)
-  bindir = get_option('prefix') / bindir
-endif
+bindir = fs.is_absolute(bindir) ? bindir : prefix / bindir
 configdata.set_quoted('NIX_BIN_DIR', bindir)
 
+mandir = get_option('mandir')
+mandir = fs.is_absolute(mandir) ? mandir : prefix / mandir
+configdata.set_quoted('NIX_MAN_DIR', mandir)
+
 config_priv_h = configure_file(
   configuration : configdata,
   output : 'cli-config-private.hh',
@@ -174,16 +177,6 @@ if host_machine.system() != 'windows'
   ]
 endif
 
-fs = import('fs')
-prefix = get_option('prefix')
-
-mandir = get_option('mandir')
-mandir = fs.is_absolute(mandir) ? mandir : prefix / mandir
-
-cpp_args= [
-  '-DNIX_MAN_DIR="@0@"'.format(mandir)
-]
-
 include_dirs = [include_directories('.')]
 
 this_exe = executable(
@@ -191,7 +184,6 @@ this_exe = executable(
   sources,
   dependencies : deps_private_subproject + deps_private + deps_other,
   include_directories : include_dirs,
-  cpp_args : cpp_args,
   link_args: linker_export_flags,
   install : true,
 )