Use the declared OpenHMD dep

Don't directly pull in the openhmd lib from the subproject. Instead,
use the dependency object it provides, so we get any provided
compiler and link flags from it automatically.

meson.build

@@ -11,20 +11,19 @@ sources = [
 	'driver_openhmd.cpp'
 ]
 
-includes = include_directories(['./subprojects/openhmd/include', './subprojects/openvr'])
+includes = include_directories(['./subprojects/openvr'])
 
 openhmd_subproject = subproject('openhmd', default_options: ['default_library=static'])
-openhmd_lib = openhmd_subproject.get_variable('openhmd_lib')
 
 deps = [
-	dependency('threads')
+	dependency('threads'),
+	dependency('openhmd', fallback : ['openhmd', 'openhmd_dep'])
 ]
 
 steamvr_openhmd_lib = library(
 	'driver_openhmd', sources,
 	include_directories : includes,
 	dependencies : deps,
-	link_with: openhmd_lib,
 	install : true,
 	version : meson.project_version(),
 	name_prefix : ''