Build error on ARM device due to ld flags

[Sebastian Gottschall]

> The packager on Arch (makepkg) has a config file (/etc/makepkg.conf)
> that is read when a package is built by it which sets the build flags.
> I just exported the flags therein on the shell then built manually to
> keep it simple (ie without explaining about the packager).  I can tell
> you that I get the identical error when I build manually as shown or
> with the packager.
the problem here is that no external flags should be set for kernel 
related builds. the kernel has its own flags

and exakt these flags must be used for wireguard and this is how it 
works. otherwise strange things will happen.
but i also never used makepkg. a plain make / make install does the job 
by itself

>
> Curiously, I only get this error when I build Wireguard on this
> platform (again reading from /etc/makepkg.conf which sets those
> flags).  I can build anything else without the error (linux kernel,
> ffmpeg, owncloud, nginx, etc.)
>
>> Am 24.01.2019 um 09:57 schrieb John:
>>> Thank you for the reply. What is odd is that I can build just fine on
>>> Arch x86_64 which uses the identical LDFLAGS.  In any case, is your
>>> recommendation to drop the -Wl portion of the LDFLAGS or so unset all
>>> ie:
>>>
>>> unset CPPFLAGS CFLAGS CXXFLAGS LDFLAGS DEBUG_CFLAGS DEBUG_CXXFLAGS
>>>
>>> On Wed, Jan 23, 2019 at 11:02 PM Sebastian Gottschall
>>> <s.gottschall at newmedia-net.de> wrote:
>>>> -Wl etc is not a valid linker flag, its a flag for gcc which passes the
>>>> following flags to the linker. so basicly the LDFLAGS are just wrong.
>>>> in general no CFLAGS or LDFLAGS should be overriden, since wireguard
>>>> uses exact he same flags which is used for compiling the kernel. so setting
>>>> custom flags should be avoided
>>>>
>>>> Am 23.01.2019 um 22:07 schrieb John:
>>>>> I am running Arch ARM (aarch64) on an ODROID-C2 using gcc v8.2.1.
>>>>> Arch ARM which ships with the following LDFLAGS as defaults,
>>>>> "-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now"
>>>>>
>>>>> When I build wireguard on this device as shown below, I get this error
>>>>> but am unsure why:
>>>>>
>>>>> ld: unrecognized option '-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
>>>>> ld: use the --help option for usage information
>>>>> make[2]: *** [scripts/Makefile.build:393:
>>>>> /scratch/WireGuard-0.0.20190123/src/wireguard.o] Error 1
>>>>> make[1]: *** [Makefile:1358:
>>>>> _module_/scratch/WireGuard-0.0.20190123/src] Error 2
>>>>> make: *** [Makefile:36: module] Error 2
>>>>>
>>>>> If I remove the '-Wl' switch from the distro default, it builds
>>>>> without error.  Any advice is appreciated.
>>>>>
>>>>> Complete build log and my FLAGS:
>>>>>
>>>>> % export CPPFLAGS="-D_FORTIFY_SOURCE=2"
>>>>> % export CFLAGS="-march=armv8-a -O2 -pipe -fstack-protector-strong -fno-plt"
>>>>> % export CXXFLAGS="-march=armv8-a -O2 -pipe -fstack-protector-strong -fno-plt"
>>>>> % export LDFLAGS="-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now"
>>>>> % export DEBUG_CFLAGS="-g -fvar-tracking-assignments"
>>>>> % export DEBUG_CXXFLAGS="-g -fvar-tracking-assignments"
>>>>>
>>>>> % cd WireGuard-0.0.20190123
>>>>> % make -j5 -C src
>>>>> make: Entering directory '/scratch/WireGuard-0.0.20190123/src'
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/wg.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/config.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/show.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/terminal.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/ipc.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/mnlg.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/encoding.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/curve25519.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/setconf.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/genkey.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/showconf.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/pubkey.o
>>>>>      CC      /scratch/WireGuard-0.0.20190123/src/tools/set.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/main.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/device.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/noise.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/peer.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/timers.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/queueing.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/send.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/receive.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/socket.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/hashtables.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/allowedips.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/ratelimiter.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/cookie.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/netlink.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20/chacha20.o
>>>>>      PERLASM /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20/chacha20-arm64.S
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/poly1305/poly1305.o
>>>>>      PERLASM /scratch/WireGuard-0.0.20190123/src/crypto/zinc/poly1305/poly1305-arm64.S
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20poly1305.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/blake2s/blake2s.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/curve25519/curve25519.o
>>>>>      LD      /scratch/WireGuard-0.0.20190123/src/tools/wg
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/compat/siphash/siphash.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/compat/dst_cache/dst_cache.o
>>>>>      CC [M]  /scratch/WireGuard-0.0.20190123/src/compat/udp_tunnel/udp_tunnel.o
>>>>>      AS [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/chacha20/chacha20-arm64.o
>>>>>      AS [M]  /scratch/WireGuard-0.0.20190123/src/crypto/zinc/poly1305/poly1305-arm64.o
>>>>>      LD [M]  /scratch/WireGuard-0.0.20190123/src/wireguard.o
>>>>> ld: unrecognized option '-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
>>>>> ld: use the --help option for usage information
>>>>> make[2]: *** [scripts/Makefile.build:393:
>>>>> /scratch/WireGuard-0.0.20190123/src/wireguard.o] Error 1
>>>>> make[1]: *** [Makefile:1358:
>>>>> _module_/scratch/WireGuard-0.0.20190123/src] Error 2
>>>>> make: *** [Makefile:36: module] Error 2
>>>>> make: Leaving directory '/scratch/WireGuard-0.0.20190123/src'