Disable installation when used as meson subproject. #1463

meson.build

@@ -12,6 +12,7 @@ nlohmann_json_multiple_headers = declare_dependency(
     include_directories: include_directories('include')
 )
 
+if not meson.is_subproject()
 install_headers('single_include/nlohmann/json.hpp', subdir: 'nlohmann')
 
 pkgc = import('pkgconfig')
@@ -19,3 +20,4 @@ pkgc.generate(name: 'nlohmann_json',
     version: meson.project_version(),
     description: 'JSON for Modern C++'
 )
+endif