on some targets, the logic for the compiler option -static seems not
to be processed when -pie is present. rather than playing
whack-a-mole, just ensure LD_PIE_SPEC specs always pass -static to ld
if either -static or -static-pie is present on the compiler driver
command line.
this may produce redundant -static arguments but it doesn't matter.
this is a critical wrong-codegen bug in gcc 9 and 10 that can have
security impact, and oddly the fix still does not seem to have been
backported, so just disable builtin memcmp expansion entirely until
there's a known-good fix.
