Attempting to detect windows to add the option you need.

sfmldemo/meson.build

@@ -1,14 +1,20 @@
 project('sfmldemo', 'cpp',
-  default_options: [
+  default_options: ['cpp_std=c++17'])
-    'default_library=static',
-    'cpp_std=c++17',
-    ])
 
-sfml_dep = dependency('sfml')
+if host_machine.system() == 'windows'
-imgui_dep = dependency('imgui-sfml')
+  defaults = ['library_default=static']
-fmt_dep = dependency('fmt')
+else
+  defaults = []
+endif
+
+dependencies = [
+  dependency('sfml'),
+  dependency('imgui-sfml'),
+  dependency('fmt'),
+]
 
 executable('sfmldemo', 'main.cpp',
   win_subsystem: 'windows',
   cpp_args: '-DFMT_HEADER_ONLY',
-  dependencies: [sfml_dep, imgui_dep, fmt_dep])
+  override_options: defaults,
+  dependencies: dependencies)

sfmldemo/reset_build.sh

@@ -0,0 +1,17 @@
+mv ./subprojects/packagecache .
+rm -rf ./subprojects ./builddir
+mkdir subprojects
+mv ./packagecache ./subprojects
+mkdir builddir
+meson wrap install flac
+meson wrap install freetype2
+meson wrap install imgui-sfml
+meson wrap install imgui
+meson wrap install libpng
+meson wrap install ogg
+meson wrap install openal-soft
+meson wrap install sfml
+meson wrap install vorbis
+meson wrap install zlib
+meson wrap install fmt
+meson setup builddir