meson: allow selecting sd-bus library via option

Roughly based on https://github.com/swaywm/sway/commit/fdbe98512a71

Co-authored-by: Peter Hutterer <peter.hutterer@who-t.net>

meson.build

@@ -83,7 +83,31 @@ dep_libxkbcommon = dependency('xkbcommon', required: false)
 config_h.set10('HAVE_LIBXKBCOMMON', dep_libxkbcommon.found())
 dep_libevdev = dependency('libevdev', required: false)
 config_h.set10('HAVE_LIBEVDEV', dep_libevdev.found())
-dep_systemd = dependency(['libsystemd', 'libelogind', 'basu'], required: get_option('liboeffis'))
+
+if not get_option('liboeffis').disabled()
+    sd_bus_provider = get_option('sd-bus-provider')
+    if sd_bus_provider == 'auto'
+        message('Trying to find an sd-bus provider...')
+        providers = ['libsystemd', 'libelogind', 'basu']
+        foreach provider: providers
+            if dependency(provider, required: false).found()
+                message('Using sd-bus provider "@0@"'.format(provider))
+                sd_bus_provider = provider
+                break
+            endif
+        endforeach
+        if sd_bus_provider  == 'auto'
+            error('Failed to find an sd-bus provider, tried @0@'.format(', '.join(providers)))
+        endif
+        summary({'sd-bus-provider': sd_bus_provider}, section: 'Conditional Features')
+    endif
+    dep_sdbus = dependency(sd_bus_provider, required: get_option('liboeffis'))
+else
+    dep_sdbus = dependency('', required: false)
+endif
+config_h.set10('HAVE_LIBSYSTEMD', dep_sdbus.found() and dep_sdbus.name() == 'libsystemd')
+config_h.set10('HAVE_LIBELOGIND', dep_sdbus.found() and dep_sdbus.name() == 'libelogind')
+config_h.set10('HAVE_BASU', dep_sdbus.found() and dep_sdbus.name() == 'basu')
 
 configure_file(output: 'config.h', configuration: config_h)
 

meson_options.txt

@@ -1,3 +1,4 @@
 option('documentation', type: 'array', value: [], choices: ['api', 'protocol'], description: 'Enable documentation builds')
+option('sd-bus-provider', type: 'combo', choices: ['auto', 'libsystemd', 'libelogind', 'basu'], value: 'auto', description: 'Provider of the sd-bus library')
 option('tests', type: 'feature', value: 'auto', description: 'Enable/disable tests')
 option('liboeffis', type: 'feature', value: 'auto', description: 'Build liboeffis.so')

src/liboeffis.c

@@ -24,11 +24,11 @@
 
 #include "config.h"
 
-#if __has_include(<systemd/sd-bus.h>)
+#if HAVE_LIBSYSTEMD
 #include <systemd/sd-bus.h>
-#elif __has_include(<elogind/sd-bus.h>)
+#elif HAVE_LIBELOGIND
 #include <elogind/sd-bus.h>
-#else
+#elif HAVE_BASU
 #include <basu/sd-bus.h>
 #endif
 

src/meson.build

@@ -142,11 +142,11 @@ pkgconfig.generate(lib_libeis,
     libraries: lib_libeis,
 )
 
-build_oeffis = dep_systemd.found()
+build_oeffis = dep_sdbus.found()
 summary({'liboeffis': build_oeffis}, section: 'Conditional Features')
 if build_oeffis
     src_liboeffis = files('liboeffis.c')
-    deps_liboeffis = [dep_libutil, dep_systemd]
+    deps_liboeffis = [dep_libutil, dep_sdbus]
 
     lib_liboeffis = library('oeffis',
         src_liboeffis,