make lib and bin optional to only compile what is wanted

meson.build

@@ -29,5 +29,12 @@ if docs_enabled
     endif
 endif
 
-subdir('lib')
-subdir('src')
+lib_enabled = get_option('lib')
+if lib_enabled
+    subdir('lib')
+endif
+
+bin_enabled = get_option('bin')
+if bin_enabled
+    subdir('src')
+endif

meson_options.txt

@@ -1,3 +1,13 @@
+option('bin',
+    type: 'boolean',
+    value: true,
+    description: 'Build the obelisk compiler'
+)
+option('lib',
+    type: 'boolean',
+    value: true,
+    description: 'Build the obelisk library'
+)
 option('docs',
     type: 'boolean',
     value: true,