[gupnp] build: Move config.h to private folder

[Jens Georg <jensgeorg src gnome org>]

commit 98b2f54fa6138c8975d5595e63b3d128e1d27072
Author: Jens Georg <mail jensge org>
Date:   Sat Jun 19 18:20:14 2021 +0200

    build: Move config.h to private folder
    
    This is necessary to use it nicely in a subproject, see
    https://mesonbuild.com/Wrap-best-practices-and-tips.html#do-not-put-configh-in-external-search-path

 internal/meson.build | 3 +++
 libgupnp/meson.build | 2 +-
 meson.build          | 6 ++----
 3 files changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/internal/meson.build b/internal/meson.build
new file mode 100644
index 0000000..4060f6a
--- /dev/null
+++ b/internal/meson.build
@@ -0,0 +1,3 @@
+config_h = configure_file(output : 'config.h', configuration : conf)
+config_h_inc = include_directories('.')
+
diff --git a/libgupnp/meson.build b/libgupnp/meson.build
index 1f79b8a..266a138 100644
--- a/libgupnp/meson.build
+++ b/libgupnp/meson.build
@@ -106,7 +106,7 @@ libgupnp = library(
     darwin_versions : darwin_versions,
     dependencies : dependencies + system_deps,
     c_args : context_manager_args,
-    include_directories: include_directories('..'),
+    include_directories: [include_directories('..'), config_h_inc],
     install: true
 )
 
diff --git a/meson.build b/meson.build
index f31e4be..0b8f298 100644
--- a/meson.build
+++ b/meson.build
@@ -18,9 +18,7 @@ add_project_arguments(cc.get_supported_arguments('-Werror=deprecated-declaration
 conf.set('GLIB_VERSION_MIN_REQUIRED', 'GLIB_VERSION_' + glib_version.underscorify())
 conf.set('GLIB_VERSION_MAX_ALLOWED', 'GLIB_VERSION_' + glib_version.underscorify())
 
-config_h = configure_file(output : 'config.h', configuration : conf)
-add_project_arguments('-DHAVE_CONFIG_H=1', language : 'c')
-
+subdir('internal')
 guul = subproject('guul', default_options : ['default_library=static'])
 
 gssdp_dep = dependency('gssdp-1.2', version : '>= 1.2.3', default_options: ['sniffer=false'])
@@ -34,7 +32,7 @@ dependencies = [
     dependency('gobject-2.0', version : '>= ' + glib_version),
     dependency('libsoup-2.4', version : '>= 2.48.0'),
     gssdp_dep,
-    dependency('libxml-2.0')
+    dependency('libxml-2.0'),
 ]
 
 subdir('libgupnp')