Revert "Add missing extern "C"."

This reverts commit 0c92b810cb6dd2f3abdf131fb00a239571d397bc.
Revert "Fix valgrind build."

This reverts commit e7d05c830d8252cedd01a7b2f8a9be3ee2ee6187.
Revert "Use the NetBSD <sys/exec_elf.h>."

This reverts commit 7d263e5a69664eb02e09a1210720075333e6b221.

Conflicts:
	libc/kernel/common/linux/elf-em.h

Signed-off-by: Paul Beeler <sparksco@gmail.com>
Revert "Make sincosl call sinl and cosl."

This reverts commit 17fbf467ad80f757f96d52b68e70af772c8e85bf.
Revert "linker: add -Wl,--exclude-libs,ALL to LDFLAGS"

This reverts commit 5f394c7d3a4cb64c7c6551eb6fd82506533d321a.