fix(build-system): fixed build system order and test env variables

src/meson.build

@@ -2,10 +2,10 @@
 subdir('resources')
 
 # Build the main source code
+subdir('config')
 subdir('dobj')
 subdir('const')
 subdir('opatIO')
 subdir('meshIO')
 subdir('probe')
 subdir('poly')
-subdir('config')

tests/meshIO/meson.build

@@ -18,5 +18,8 @@ foreach test_file : test_sources
   )
 
   # Add the executable as a test
-  test(exe_name, test_exe)
+  test(
+    exe_name,
+    test_exe,
+    env: ['MESON_SOURCE_ROOT=' + meson.project_source_root(), 'MESON_BUILD_ROOT=' + meson.project_build_root()])
 endforeach

tests/poly/meson.build

@@ -16,5 +16,8 @@ foreach test_file : test_sources
   )
 
   # Add the executable as a test
-  test(exe_name, test_exe)
+  test(
+    exe_name,
+    test_exe,
+    env: ['MESON_SOURCE_ROOT=' + meson.project_source_root(), 'MESON_BUILD_ROOT=' + meson.project_build_root()])
 endforeach