>2) NetBSD-current won't build with unmodified GENERIC (i386).  It
>   fails, when it tries to compile "linux_sysctl.c".
>
>=================================================================
>compile  GENERIC/linux_sysctl.o
>cc -ffreestanding -O2 -Werror -Wall -Wno-main -Wno-format-zero-length -Wpointer-arith -Wmissing-prototypes -Wstrict-prototypes -Wno-sign-compare -Wno-uninitialized -Di386 -I. -I../../../../arch -I../../../.. -nostdinc -DLKM -DMAXUSERS=32 -D_KERNEL -D_KERNEL_OPT -c ../../../../compat/linux/common/linux_sysctl.c
>../../../../compat/linux/common/linux_sysctl.c:75: unknown field `__sysc_ustr' specified in initializer
>../../../../compat/linux/common/linux_sysctl.c:75: unknown field `__sysc_sdatum' specified in initializer
>...

mine can.

  this# cd /usr/src/sys/arch/i386/conf/
  this# config GENERIC
  Build directory is ../compile/GENERIC
  Don't forget to run "make depend"
  this# cd ../compile/GENERIC/
  this# make linux_sysctl.o
  #   compile  GENERIC/linux_sysctl.o
  cc -ffreestanding -O2 -Werror -Wall -Wno-main -Wno-format-zero-length -Wpointer-arith -Wmissing-prototypes -Wstrict-prototypes -Wno-sign-compare -Di386 -I. -I../../../../arch -I../../../.. -nostdinc -DLKM -DMAXUSERS=32 -D_KERNEL -D_KERNEL_OPT -c ../../../../compat/linux/common/linux_sysctl.c
  this# 

what revision of sys/sysctl.h and compat/linux/common/linux_sysctl.c
do you have?  what does cc -v report?

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