build(cross): macOS cross compilation

macos cross compilation now works. macos binaries can be compiled on
linux with osxcross installed and built

meson.build

@@ -30,6 +30,7 @@ message('Found CXX compiler: ' + meson.get_compiler('cpp').get_id())
 message('C++ standard set to: ' + get_option('cpp_std'))
 
 cppc = meson.get_compiler('cpp')
+cc = meson.get_compiler('c')
 
 
 if cppc.get_id() == 'clang'
@@ -72,6 +73,11 @@ if not cppc.has_header('format')
 endif
 
 
+ignore_unused_args = '-Wno-unused-command-line-argument'
+
+add_global_arguments(ignore_unused_args, language: 'cpp')
+add_global_arguments(ignore_unused_args, language: 'c')
+
 
 
 # For Eigen