dlang: add test case for root include_directory #9250

test cases/d/12 root include directory/meson.build

@@ -0,0 +1,7 @@
+project('some', 'd')
+
+project_dep = declare_dependency(
+    include_directories: ['.'],
+)
+subdir('some')
+

test cases/d/12 root include directory/some/dlang/code.d

@@ -0,0 +1,7 @@
+void foo() {} 
+
+version (Windows)
+{
+    import core.sys.windows.dll;
+    mixin SimpleDllMain;
+}

test cases/d/12 root include directory/some/dlang/meson.build

@@ -0,0 +1,8 @@
+code_lib = library('code',
+    ['code.d'],
+    dependencies: [project_dep])
+
+code_dep = declare_dependency(
+    link_with: code_lib,
+    dependencies: project_dep
+)

test cases/d/12 root include directory/some/meson.build

@@ -0,0 +1 @@
+subdir('dlang')