buildgcc: Build GMP --with-pic if GCC defaults to -pie

[iseeareddoor]

GCC 6 can optionally default to building all binaries as position
independent executables (PIE). This breaks linking against static
libraries that are compiled without position independent code (PIC).

Building GMP --with-pic in this case seems to be the least fragile
solution.

TEST=Run make all and make BUILDGCC_OPTIONS=-b build-i386 in
util/crossgcc on Debian Stretch.

Change-Id: I5f3185af9c8d599379a628e18724b217b88be974
Signed-off-by: Nico Huber nico.huber@secunet.com
Reviewed-on: https://review.coreboot.org/17936
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel paulepanter@users.sourceforge.net
Reviewed-by: Jonathan Neuschäfer j.neuschaefer@gmx.net

[iseeareddoor]

since there are no issues allowed here, I opened a pull request instead - if you rather want such things to be reported against the main heads repository, please tell.

please cherry-pick this commit from upstream (coreboot@8bbd596), without it building with GCC-6 (Debian Stretch/Sid) is broken because of the default PIE compile flags.

I verified that with it included the crossgcc build works and I get a qemu.rom built which outputs some coreboot stuff on the console when started with Qemu - there is little documentation on what is supposed to work with Qemu and how to test it?