diff --git a/src/libcmd/meson.build b/src/libcmd/meson.build
index 4145f408a..5925cb6f0 100644
--- a/src/libcmd/meson.build
+++ b/src/libcmd/meson.build
@@ -63,9 +63,7 @@ add_project_arguments(
   # It would be nice for our headers to be idempotent instead.
   '-include', 'config-util.hh',
   '-include', 'config-store.hh',
-  # '-include', 'config-fetchers.h',
   '-include', 'config-expr.hh',
-  '-include', 'config-main.hh',
   '-include', 'config-cmd.hh',
   language : 'cpp',
 )
@@ -93,7 +91,7 @@ sources = files(
 
 include_dirs = [include_directories('.')]
 
-headers = [config_h] + files(
+headers = files(
   'built-path.hh',
   'command-installable-value.hh',
   'command.hh',
@@ -116,6 +114,7 @@ headers = [config_h] + files(
 this_library = library(
   'nixcmd',
   sources,
+  config_h,
   dependencies : deps_public + deps_private + deps_other,
   prelink : true, # For C++ static initializers
   install : true,
diff --git a/src/libexpr-c/meson.build b/src/libexpr-c/meson.build
index 9487132cf..8405525ca 100644
--- a/src/libexpr-c/meson.build
+++ b/src/libexpr-c/meson.build
@@ -14,8 +14,6 @@ cxx = meson.get_compiler('cpp')
 
 subdir('nix-meson-build-support/deps-lists')
 
-configdata = configuration_data()
-
 deps_private_maybe_subproject = [
   dependency('nix-util'),
   dependency('nix-store'),
@@ -27,14 +25,6 @@ deps_public_maybe_subproject = [
 ]
 subdir('nix-meson-build-support/subprojects')
 
-# TODO rename, because it will conflict with downstream projects
-configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
-
-config_h = configure_file(
-  configuration : configdata,
-  output : 'config-expr.h',
-)
-
 add_project_arguments(
   # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
   # It would be nice for our headers to be idempotent instead.
@@ -44,10 +34,6 @@ add_project_arguments(
   '-include', 'config-store.hh',
   '-include', 'config-expr.hh',
 
-  # From C libraries, for our public, installed headers too
-  '-include', 'config-util.h',
-  '-include', 'config-store.h',
-  '-include', 'config-expr.h',
   language : 'cpp',
 )
 
@@ -61,7 +47,7 @@ sources = files(
 
 include_dirs = [include_directories('.')]
 
-headers = [config_h] + files(
+headers = files(
   'nix_api_expr.h',
   'nix_api_external.h',
   'nix_api_value.h',
diff --git a/src/libexpr-tests/meson.build b/src/libexpr-tests/meson.build
index 667a0d7b7..9f6edb9b3 100644
--- a/src/libexpr-tests/meson.build
+++ b/src/libexpr-tests/meson.build
@@ -41,9 +41,6 @@ add_project_arguments(
   '-include', 'config-util.hh',
   '-include', 'config-store.hh',
   '-include', 'config-expr.hh',
-  '-include', 'config-util.h',
-  '-include', 'config-store.h',
-  '-include', 'config-expr.h',
   language : 'cpp',
 )
 
diff --git a/src/libflake-c/meson.build b/src/libflake-c/meson.build
index 85d20644d..469e0ade4 100644
--- a/src/libflake-c/meson.build
+++ b/src/libflake-c/meson.build
@@ -14,8 +14,6 @@ cxx = meson.get_compiler('cpp')
 
 subdir('nix-meson-build-support/deps-lists')
 
-configdata = configuration_data()
-
 deps_private_maybe_subproject = [
   dependency('nix-util'),
   dependency('nix-store'),
@@ -29,14 +27,6 @@ deps_public_maybe_subproject = [
 ]
 subdir('nix-meson-build-support/subprojects')
 
-# TODO rename, because it will conflict with downstream projects
-configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
-
-config_h = configure_file(
-  configuration : configdata,
-  output : 'config-flake.h',
-)
-
 add_project_arguments(
   # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
   # It would be nice for our headers to be idempotent instead.
@@ -48,11 +38,6 @@ add_project_arguments(
   # not generated (yet?)
   # '-include', 'config-flake.hh',
 
-  # From C libraries, for our public, installed headers too
-  '-include', 'config-util.h',
-  '-include', 'config-store.h',
-  '-include', 'config-expr.h',
-  '-include', 'config-flake.h',
   language : 'cpp',
 )
 
@@ -64,7 +49,7 @@ sources = files(
 
 include_dirs = [include_directories('.')]
 
-headers = [config_h] + files(
+headers = files(
   'nix_api_flake.h',
 )
 
diff --git a/src/libmain-c/meson.build b/src/libmain-c/meson.build
index d875d2c3f..0e9380a12 100644
--- a/src/libmain-c/meson.build
+++ b/src/libmain-c/meson.build
@@ -14,8 +14,6 @@ cxx = meson.get_compiler('cpp')
 
 subdir('nix-meson-build-support/deps-lists')
 
-configdata = configuration_data()
-
 deps_private_maybe_subproject = [
   dependency('nix-util'),
   dependency('nix-store'),
@@ -27,14 +25,6 @@ deps_public_maybe_subproject = [
 ]
 subdir('nix-meson-build-support/subprojects')
 
-# TODO rename, because it will conflict with downstream projects
-configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
-
-config_h = configure_file(
-  configuration : configdata,
-  output : 'config-main.h',
-)
-
 add_project_arguments(
   # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
   # It would be nice for our headers to be idempotent instead.
@@ -42,12 +32,7 @@ add_project_arguments(
   # From C++ libraries, only for internals
   '-include', 'config-util.hh',
   '-include', 'config-store.hh',
-  '-include', 'config-main.hh',
 
-  # From C libraries, for our public, installed headers too
-  '-include', 'config-util.h',
-  '-include', 'config-store.h',
-  '-include', 'config-main.h',
   language : 'cpp',
 )
 
@@ -59,7 +44,7 @@ sources = files(
 
 include_dirs = [include_directories('.')]
 
-headers = [config_h] + files(
+headers = files(
   'nix_api_main.h',
 )
 
diff --git a/src/libmain/meson.build b/src/libmain/meson.build
index 00f945f49..e6f6d6de9 100644
--- a/src/libmain/meson.build
+++ b/src/libmain/meson.build
@@ -74,7 +74,7 @@ endif
 
 include_dirs = [include_directories('.')]
 
-headers = [config_h] + files(
+headers = files(
   'common-args.hh',
   'loggers.hh',
   'plugin.hh',
@@ -85,6 +85,7 @@ headers = [config_h] + files(
 this_library = library(
   'nixmain',
   sources,
+  config_h,
   dependencies : deps_public + deps_private + deps_other,
   prelink : true, # For C++ static initializers
   install : true,
diff --git a/src/libstore-c/meson.build b/src/libstore-c/meson.build
index 17d18609f..2e2275fee 100644
--- a/src/libstore-c/meson.build
+++ b/src/libstore-c/meson.build
@@ -14,8 +14,6 @@ cxx = meson.get_compiler('cpp')
 
 subdir('nix-meson-build-support/deps-lists')
 
-configdata = configuration_data()
-
 deps_private_maybe_subproject = [
   dependency('nix-util'),
   dependency('nix-store'),
@@ -25,14 +23,6 @@ deps_public_maybe_subproject = [
 ]
 subdir('nix-meson-build-support/subprojects')
 
-# TODO rename, because it will conflict with downstream projects
-configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
-
-config_h = configure_file(
-  configuration : configdata,
-  output : 'config-store.h',
-)
-
 add_project_arguments(
   # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
   # It would be nice for our headers to be idempotent instead.
@@ -41,9 +31,6 @@ add_project_arguments(
   '-include', 'config-util.hh',
   '-include', 'config-store.hh',
 
-  # From C libraries, for our public, installed headers too
-  '-include', 'config-util.h',
-  '-include', 'config-store.h',
   language : 'cpp',
 )
 
@@ -55,7 +42,7 @@ sources = files(
 
 include_dirs = [include_directories('.')]
 
-headers = [config_h] + files(
+headers = files(
   'nix_api_store.h',
 )
 
diff --git a/src/libstore-tests/meson.build b/src/libstore-tests/meson.build
index 3ba0795e9..9f3d8e1d4 100644
--- a/src/libstore-tests/meson.build
+++ b/src/libstore-tests/meson.build
@@ -45,8 +45,6 @@ add_project_arguments(
   # It would be nice for our headers to be idempotent instead.
   '-include', 'config-util.hh',
   '-include', 'config-store.hh',
-  '-include', 'config-util.h',
-  '-include', 'config-store.h',
   language : 'cpp',
 )
 
diff --git a/src/libstore/meson.build b/src/libstore/meson.build
index 7b38bafe0..a4d413f04 100644
--- a/src/libstore/meson.build
+++ b/src/libstore/meson.build
@@ -67,6 +67,7 @@ endforeach
 has_acl_support = cxx.has_header('sys/xattr.h') \
   and cxx.has_function('llistxattr') \
   and cxx.has_function('lremovexattr')
+# TODO: used in header - make proper public header and make sure it's included. Affects ABI!
 configdata.set('HAVE_ACL_SUPPORT', has_acl_support.to_int())
 
 if host_machine.system() == 'darwin'
diff --git a/src/libutil-c/meson.build b/src/libutil-c/meson.build
index ac1297665..2733a33ba 100644
--- a/src/libutil-c/meson.build
+++ b/src/libutil-c/meson.build
@@ -23,7 +23,6 @@ deps_public_maybe_subproject = [
 ]
 subdir('nix-meson-build-support/subprojects')
 
-# TODO rename, because it will conflict with downstream projects
 configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
 
 config_h = configure_file(
@@ -38,8 +37,6 @@ add_project_arguments(
   # From C++ libraries, only for internals
   '-include', 'config-util.hh',
 
-  # From C libraries, for our public, installed headers too
-  '-include', 'config-util.h',
   language : 'cpp',
 )
 
@@ -51,7 +48,7 @@ sources = files(
 
 include_dirs = [include_directories('.')]
 
-headers = [config_h] + files(
+headers = files(
   'nix_api_util.h',
 )
 
@@ -64,6 +61,7 @@ subdir('nix-meson-build-support/windows-version')
 this_library = library(
   'nixutilc',
   sources,
+  config_h,
   dependencies : deps_public + deps_private + deps_other,
   include_directories : include_dirs,
   link_args: linker_export_flags,
diff --git a/src/libutil-c/nix_api_util.cc b/src/libutil-c/nix_api_util.cc
index 992ea0a2a..3e061d53e 100644
--- a/src/libutil-c/nix_api_util.cc
+++ b/src/libutil-c/nix_api_util.cc
@@ -7,6 +7,8 @@
 #include <cxxabi.h>
 #include <typeinfo>
 
+#include "config-util.h"
+
 nix_c_context * nix_c_context_create()
 {
     return new nix_c_context();
diff --git a/src/libutil-tests/meson.build b/src/libutil-tests/meson.build
index ad2c61711..f982d6cf6 100644
--- a/src/libutil-tests/meson.build
+++ b/src/libutil-tests/meson.build
@@ -32,11 +32,16 @@ deps_private += rapidcheck
 gtest = dependency('gtest', main : true)
 deps_private += gtest
 
+configdata = configuration_data()
+configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
+
+config_h = configure_file(
+  configuration : configdata,
+  output : 'config-util-tests.hh',
+)
+
 add_project_arguments(
-  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
-  # It would be nice for our headers to be idempotent instead.
-  '-include', 'config-util.hh',
-  '-include', 'config-util.h',
+  '-include', 'config-util-tests.hh',
   language : 'cpp',
 )
 
@@ -79,6 +84,7 @@ include_dirs = [include_directories('.')]
 this_exe = executable(
   meson.project_name(),
   sources,
+  config_h,
   dependencies : deps_private_subproject + deps_private + deps_other,
   include_directories : include_dirs,
   # TODO: -lrapidcheck, see ../libutil-support/build.meson
diff --git a/src/libutil/meson.build b/src/libutil/meson.build
index f3eac5cdc..3c0cb0d6b 100644
--- a/src/libutil/meson.build
+++ b/src/libutil/meson.build
@@ -33,12 +33,14 @@ check_funcs = [
   'pipe2',
   # Optionally used to preallocate files to be large enough before
   # writing to them.
+  # WARNING: define also used in libstore
   'posix_fallocate',
   # Optionally used to get more information about processes failing due
   # to a signal on Unix.
   'strsignal',
   # Optionally used to try to close more file descriptors (e.g. before
   # forking) on Unix.
+  # WARNING: also used in libexpr
   'sysconf',
   # Optionally used for changing the mtime of files and symlinks.
   'utimensat',
diff --git a/src/nix/meson.build b/src/nix/meson.build
index 79ad840f6..1ad53c807 100644
--- a/src/nix/meson.build
+++ b/src/nix/meson.build
@@ -57,9 +57,6 @@ add_project_arguments(
   '-include', 'config-util.hh',
   '-include', 'config-store.hh',
   '-include', 'config-expr.hh',
-  #'-include', 'config-fetchers.hh',
-  '-include', 'config-main.hh',
-  '-include', 'config-cmd.hh',
   '-include', 'config-nix-cli.hh',
   language : 'cpp',
 )
diff --git a/tests/functional/plugins/meson.build b/tests/functional/plugins/meson.build
index 3d6b2f0e1..13acdbbc5 100644
--- a/tests/functional/plugins/meson.build
+++ b/tests/functional/plugins/meson.build
@@ -6,7 +6,6 @@ libplugintest = shared_module(
     # It would be nice for our headers to be idempotent instead.
     '-include', 'config-util.hh',
     '-include', 'config-store.hh',
-    # '-include', 'config-fetchers.hh',
     '-include', 'config-expr.hh',
   ],
   dependencies : [