build: fix header files for Plan 9
The "elf.h" header changes involve only comments, the released
Plan 9 C preprocessing function does not cope with multiline
comments following the #define keyword. All multiline comments
have been moved to the line above the associated definition.
Sigh! Fixing the Plan 9 compiler is not an option.
<time.h> does not exist in the Plan 9 Native library. I have
moved it from src/cmd/ld/pe.h to include/u.h. RSC correctly points
out that this copy of <u.h> is not the one used to compile the
Go release on Plan 9 platforms.
R=golang-dev
CC=golang-dev, rsc
https://golang.org/cl/
4574042