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.
new patch: 0017-c++-abi-break.diff fixes a C++ ABI break regression.
0010-static-pie-support.diff was removed as it doesn't apply anymore,
and forward-porting it requires arcane knowledge of GCC details.
the patches 0018 and 0019 have been copied from GCC 7.3.0. the static
pie patch from GCC 6.4.0, renumbered 0020, depends on the reversions
they make.
