here comes a helper script

run python3 ./setup.py in the root directory, this will create a
meson.build and a directory called subdirectry.

You can now simply use the meson.build script as "main" project, all
other projects will be build in this.

meson.build.in

@@ -0,0 +1,10 @@
+project('efl-examples',
+  'c',
+  version: '1.0'
+)
+
+subprojects = $subprojects
+
+foreach subp : subprojects
+   subproject(subp)
+endforeach

setup.py

@@ -0,0 +1,59 @@
+#!/usr/bin/python3
+import os
+from string import Template
+
+supported_languages = ["c", "csharp", "cxx"]
+directories = ["apps", "reference", "tutorial"] # "examples", "legacy-examples"
+goals = []
+subprojects = []
+
+class SubProjectGoal:
+  def __init__(self, language, path):
+    self.language = language
+    self.path = path
+
+  def verify(self):
+    assert os.path.isdir(self.path)
+    assert os.path.isfile(os.path.join(self.path, 'meson.build'))
+
+  def flush(self):
+    os.symlink(os.path.join('..', self.path), os.path.realpath(os.path.join('subprojects', self.link_file_name())))
+
+  def link_file_name(self):
+    return self.language+'-'+os.path.basename(self.path)
+
+for directory in directories:
+  for lang in supported_languages:
+      explore_dir = os.path.join(directory, lang)
+      if os.path.isdir(explore_dir):
+        meson_build_file = os.path.join(explore_dir, "meson.build")
+        if os.path.isfile(meson_build_file):
+            goals.append(SubProjectGoal(lang, explore_dir))
+        else:
+          for content in os.listdir(explore_dir):
+            sub = os.path.join(explore_dir, content)
+            if os.path.isdir(sub):
+              goals.append(SubProjectGoal(lang, sub))
+
+if not os.path.isdir('./subprojects'):
+  os.mkdir('./subprojects')
+else:
+  for content in os.listdir('./subprojects'):
+    os.unlink(os.path.join('subprojects', content))
+
+for subproject in goals:
+  subproject.verify()
+  subproject.flush()
+  subprojects.append(subproject.link_file_name())
+
+content = { 'subprojects' : '[\''+'\',\''.join(subprojects)+'\']'}
+
+meson_in = open('meson.build.in')
+meson_temp = Template(meson_in.read())
+content = meson_temp.substitute(content)
+
+if os.path.isfile('meson.build'):
+  os.unlink('meson.build')
+
+meson_out = open('meson.build', 'a')
+meson_out.write(content)