plug-ins: replace s/printf/g_printf/
When cross-compiling, I got various linking errors for printf() calls:
> undefined reference to `libintl_printf'
I am unsure why, since this is not recent code, and it used to build
fine with mingw64 compilers (last I cross-built, which is many months
ago). Anyway g_printf() works fine, all necessary libs are already
linked, and it is supposed to be a synonym. So let's just go the easy
way and use g_printf() only.
(cherry picked from commit
c49afa4f84c70538f7ed30784569bb4d32b159c0)