Had to rename sfml to sfmlbackend because on Windows the filesystem is case insensitive so include <SFML/*> was accidentally including _my_ <sfml/config.hpp> file.

meson.build

@@ -72,15 +72,15 @@ sources = [
   'src/dbc.cpp',
   'src/guecs.cpp',
   'src/lel.cpp',
-  'src/sfml/components.cpp',
+  'src/sfmlbackend/components.cpp',
 ]
 
 sfml_impl = [
-  'src/sfml/config.cpp',
-  'src/sfml/backend.cpp',
-  'src/sfml/shaders.cpp',
-  'src/sfml/sound.cpp',
-  'src/sfml/textures.cpp',
+  'src/sfmlbackend/config.cpp',
+  'src/sfmlbackend/backend.cpp',
+  'src/sfmlbackend/shaders.cpp',
+  'src/sfmlbackend/sound.cpp',
+  'src/sfmlbackend/textures.cpp',
 ]
 
 lel_guecs_inc = include_directories('include')
@@ -97,9 +97,11 @@ lel_guecs_dep = declare_dependency(
   link_with: lel_guecs_lib,
   include_directories: lel_guecs_inc)
 
-executable('runtests', [
-  'src/sfml/config.cpp',
+executable('runtests', sfml_impl + [
   'tests/lel.cpp',
+  'tests/shaders.cpp',
+  'tests/sound.cpp',
+  'tests/textures.cpp',
   'tests/guecs.cpp',
   ],
   cpp_args: cpp_args,
@@ -109,12 +111,12 @@ executable('runtests', [
   link_with: [lel_guecs_lib],
   dependencies: dependencies + [catch2])
 
-#executable('calc', sfml_impl + [
-#  'demos/calc.cpp',
-#  ],
-#  cpp_args: cpp_args,
-#  link_args: link_args,
-#  override_options: exe_defaults,
-#  include_directories: lel_guecs_inc,
-#  link_with: [lel_guecs_lib],
-#  dependencies: dependencies)
+executable('calc', sfml_impl + [
+  'demos/calc.cpp',
+  ],
+  cpp_args: cpp_args,
+  link_args: link_args,
+  override_options: exe_defaults,
+  include_directories: lel_guecs_inc,
+  link_with: [lel_guecs_lib],
+  dependencies: dependencies)