Status of cross-building the C++ branch

Build environment:

(If you need any help reproducing this, I'm o11c on FreeNode and
usually idle on #gdb, though my bouncer is going down for maintenance
this weekend)

* Host OS: Debian testing (stretch) amd64 (not important except that
it's running systemd)
* Container manager: systemd-nspawn 227, in non-boot mode (but
debootstrap put a full system so it is bootable, you just can't run a
command automatically in that case, unless they've fixed the bug in
`machinectl shell` yet - this may vary depending on where you got your
systemd from)
* Container OS:
** For amd64 and i386, normal toolchain (gcc 4.9) from Debian Jessie
** For x32, normal toolchain (gcc 5) from Debian-Ports Sid
** For cross arches, the arch was added via `dpkg --add-architecture`
and the emdebian toolchain was used (gcc 4.9).
*** For mips, the provided toolchain was outdated and uninstallable,
so it was rebuilt from source
*** For s390x, the toolchain was not provided, but this was a trivial change.
**** See the *binary* package cross-gcc-dev to create a new source
package for the cross compiler, then build it.
**** See the *source* package cross-binutils to create a new binary
package for the cross, or use the one from sid.
**** Use `dpkg-buildpackage -us -uc` to build a Debian package.
* Git:
** Remote: git://github.com/palves/gdb.git
** Branch: palves/cxx-conversion-attempt-part-2-no-fpermissive
** Commit: 86ce09a70326a221b49755a589bf3622a667b265


Configure arguments:

--build=build=x86_64-linux-gnu
--host= (see list below)
--enable-build-with-cxx
--enable-targets=all

--disable-binutils
--disable-elfcpp
--disable-gas
--disable-gold
--disable-gprof
--disable-ld

Triples:

x86_64-linux-gnu
i586-linux-gnu
x86_64-linux-gnux32

aarch64-linux-gnu
arm-linux-gnueabi
arm-linux-gnueabihf
mips-linux-gnu
mipsel-linux-gnu
powerpc-linux-gnu
powerpc64le-linux-gnu
s390x-linux-gnu

Results:

All 3 native architectures passed; all 8 foreign architectures failed
with few errors.

I first ran `make -j4 -k` so that as much as possible would be built,
then `make -j1 -k` and recorded stdout and stderr to the same file.

The full errors are at
https://gist.github.com/o11c/61a02a3a999b952d5710 but I have taken the
repeated the main errors below.

arm64:
gdb/nat/aarch64-linux-hw-point.c:564:64: error: 'count' cannot appear
in a constant-expression

armel and armhf:
opcodes/sh64-dis.c:462: undefined reference to `sh64_get_contents_type'
opcodes/sh64-dis.c:476: undefined reference to `sh64_get_contents_type'

mips and mipsel:
sim/mips/micromips.igen:49: undefined reference to
`micromips_instruction_decode'

powerpc and ppc64el:
gdb/ppc-linux-nat.c:1730:40: error: invalid conversion from 'int' to
'target_hw_bp_type' [-fpermissive]
gdb/ppc-linux-nat.c:1758:40: error: invalid conversion from 'int' to
'target_hw_bp_type' [-fpermissive]

gdb/remote-sim.c:155:27: error: invalid conversion from 'void*' to
'SIM_DESC {aka sim_state*}' [-fpermissive]
gdb/remote-sim.c:157:55: error: invalid conversion from 'void*' to
'sim_inferior_data*' [-fpermissive]
gdb/remote-sim.c:175:48: error: invalid conversion from 'void*' to
'sim_inferior_data*' [-fpermissive]
gdb/remote-sim.c:260:40: error: invalid conversion from 'void*' to
'sim_inferior_data*' [-fpermissive]
gdb/remote-sim.c:770:34: error: invalid conversion from 'void*' to
'sim_inferior_data*' [-fpermissive]
gdb/remote-sim.c:852:28: error: invalid conversion from 'void*' to
'resume_data*' [-fpermissive]
gdb/remote-sim.c:1037:22: error: invalid conversion from 'int' to
'gdb_signal' [-fpermissive]
gdb/remote-sim.c:1043:25: error: invalid conversion from 'int' to
'gdb_signal' [-fpermissive]
gdb/remote-sim.c:1201:72: error: invalid conversion from 'void*' to
'sim_inferior_data*' [-fpermissive]
gdb/remote-sim.c:1234:71: error: invalid conversion from 'void*' to
'sim_inferior_data*' [-fpermissive]

s390x:

gdb/../include/libiberty.h:711:38: error: invalid conversion from
'void*' to 'gdb_byte* {aka unsigned char*}' [-fpermissive]


Note that I have not attempted to cross-build master yet to see if any
of these errors are there too, and I'm not sure exactly whether any
features disable themselves during a cross build.

-Ben

-Ben