build: fix errors found by muon analyze (#358)

I found a few small errors while testing muon analyze on this project.

meson.build

@@ -544,12 +544,15 @@ config.set('TAISEI_BUILDCONF_TESTING_STAGES', use_testing_stages)
 
 # Stolen from Sway
 # Compute the relative path used by compiler invocations.
-source_root = meson.current_source_dir().split('/')
-build_root = meson.project_build_root().split('/')
+source_root = meson.current_source_dir()
+build_root = meson.project_build_root()
 if build_machine.system() == 'windows'
     source_root = source_root.replace('\\', '/')
     build_root = build_root.replace('\\', '/')
 endif
+source_root = source_root.split('/')
+build_root = build_root.split('/')
+
 relative_dir_parts = []
 i = 0
 in_prefix = true

meson_options.txt

@@ -72,7 +72,7 @@ option(
 option(
     'install_angle',
     type : 'boolean',
-    value : 'false',
+    value : false,
     description : 'Install pre-built ANGLE libraries. Required for Windows/macOS OpenGL ES 2.0/3.0'
 )
 
@@ -217,6 +217,6 @@ option(
 option(
     'stages_live_reload',
     type : 'boolean',
-    value : 'false',
+    value : false,
     description : 'Enable live-reloading workflow for stages (for development only)'
 )

src/audio/meson.build

@@ -18,7 +18,7 @@ if default_audio_backend == 'auto'
     if default_audio_backend == 'auto'
         audio_backends_prio_opts = []
         foreach audio_backend : audio_backends_prio
-            audio_backends_prio_opts + f'a_@audio_backend@'
+            audio_backends_prio_opts += f'a_@audio_backend@'
         endforeach
         audio_backends_prio_opts = ', '.join(audio_backends_prio_opts)
 

src/renderer/meson.build

@@ -25,7 +25,7 @@ if default_renderer == 'auto'
     if default_renderer == 'auto'
         renderers_prio_opts = []
         foreach renderer : renderers_prio
-            renderers_prio_opts + f'r_@renderer@'
+            renderers_prio_opts += f'r_@renderer@'
         endforeach
         renderers_prio_opts = ', '.join(renderers_prio_opts)