uapi/if_ether.h: move __UAPI_DEF_ETHHDR libc define

This fixes a compile problem of some user space applications by not including linux/libc-compat.h in uapi/if_ether.h. linux/libc-compat.h checks which "features" the header files, included from the libc, provide to make the Linux kernel uapi header files only provide no conflicting structures and enums. If a user application mixes kernel headers and libc headers it could happen that linux/libc-compat.h gets included too early where not all other libc headers are included yet. Then the linux/libc-compat.h would not prevent all the redefinitions and we run into compile problems. This patch removes the include of linux/libc-compat.h from uapi/if_ether.h to fix the recently introduced case, but not all as this is more or less impossible. It is no problem to do the check directly in the if_ether.h file and not in libc-compat.h as this does not need any fancy glibc header detection as glibc never provided struct ethhdr and should define __UAPI_DEF_ETHHDR by them self when they will provide this. The following test program did not compile correctly any more: #include <linux/if_ether.h> #include <netinet/in.h> #include <linux/in.h> int main(void) { return 0; }

HMHauke Mehrtens committed 8 years ago