Move files into subdirectories and improve meson

.gitlab-ci.yml

@@ -4,7 +4,7 @@ test:
   script:
     - meson setup build -D b_sanitize=address,undefined
     - meson compile -C build
-    - cppcheck --error-exitcode=1 *.c
+    - cppcheck --error-exitcode=1 src/*.c
     - export ASAN_OPTIONS=symbolize=1:debug=1:detect_leaks=1:strict_string_checks=1:detect_stack_use_after_return=1:check_initialization_order=1:strict_init_order=1
     - export FML="$(readlink -f ./build/fml)"
     - export FML_REF=/cfml/fml

meson.build

-project('fml', 'c',
-  version : '0.1',
-  default_options : ['c_std=c11', 'warning_level=3'])
+project(
+  'fml',
+  'c',
+  version: '0.1',
+  default_options: ['c_std=c11', 'warning_level=2'],
+)
 exe = executable('fml',
-  'example_main.c',
-  'arena.c',
-  'parser.c',
-  install : true)
+  sources: files(
+    'reference/arena.c',
+    'reference/parser.c',
+    'src/main.c',
+  ),
+  include_directories: include_directories(
+    'src',
+    'reference'
+  ),
+  install: true,
+)