Bug#1014091: armhf: gcc has wrong configuration

[Mathieu Malaterre <malat@debian.org>]

Package: gcc-11
Version: 11.3.0-3

This is a followup to bug #928224. It turns out that gcc-11 is now
generating neon instructions, which contradicts our definition of
armhf.

Reference:

$ ssh abel.debian.org
[...]
malat@abel ~ % gcc-11 --verbose
Using built-in specs.
COLLECT_GCC=gcc-11
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/11/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Debian
11.3.0-3' --with-bugurl=file:///usr/share/doc/gcc-11/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2
--prefix=/usr --with-gcc-major-version-only --program-suffix=-11
--program-prefix=arm-linux-gnueabihf- --enable-shared
--enable-linker-build-id --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --libdir=/usr/lib
--enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-libitm --disable-libquadmath --disable-libquadmath-support
--enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-sjlj-exceptions
--with-arch=armv7-a+fp --with-float=hard --with-mode=thumb
--disable-werror --enable-checking=release --build=arm-linux-gnueabihf
--host=arm-linux-gnueabihf --target=arm-linux-gnueabihf
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.3.0 (Debian 11.3.0-3)

I suspect the issue is the following:

[...]
--with-arch=armv7-a+fp
[...]

I believe gcc-11 and above needs instead something like:

[...]
--with-arch=armv7-a+vfpv3-fp16+nosimd
[...]