configure.ac: make possible to compile with -ffunction/data-sections
configure.ac: make possible to compile with -ffunction/data-sections

The -ffunction-sections and -fdata-sections, if supported, can enable
the linker to do some amount of dead code elimination.  Basically a
very basic form of LTO.

Signed-off-by: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@linux.intel.com>

techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm