That you are using Meson is an important bit of information.
I can reproduce the error when using Meson on Windows/MSYS2. And this is because our Meson setup does *not* `WIN32`.
The following patch defines it and the build succeeds: ```diff diff --git a/meson.build b/meson.build index 6944a423b..bf725bd9b 100644 --- a/meson.build +++ b/meson.build @@ -202,6 +202,10 @@ if (gnu_source) basic_cflags += '-D_GNU_SOURCE' endif
+if host_machine.system() == 'windows' + basic_cflags += '-DWIN32=1' +endif + # CFLAGS common between Geany and bundled plugins def_cflags = basic_cflags + [ '-DGTK', ```
This raises two questions, mainly targeted to @kugel-: - why did this not fail in the past when we tested Meson support on Windows? - is there a better way or place in `meson.build` to add the define?