>>> botan 2.17.3 Extracting
xzcat /home/buildroot/autobuild/run/instance-2/dl/botan/Botan-2.17.3.tar.xz | tar --strip-components=1 -C /home/buildroot/autobuild/run/instance-2/output-1/build/botan-2.17.3   -xf -
>>> botan 2.17.3 Patching

Applying 0001-Add--extra-libs-option-and-group-l-flags-from-LDFLAGS-to-the-end.patch using patch: 
patching file configure.py
Hunk #2 succeeded at 2010 (offset -13 lines).
Hunk #3 succeeded at 2140 (offset -18 lines).
Hunk #4 succeeded at 3016 (offset -23 lines).
patching file src/build-data/makefile.in
Hunk #1 succeeded at 21 (offset 1 line).

Applying 0002-Avoid-empty-l.patch using patch: 
patching file configure.py
Hunk #1 succeeded at 2014 (offset -13 lines).
>>> botan 2.17.3 Configuring
(cd /home/buildroot/autobuild/run/instance-2/output-1/build/botan-2.17.3; PATH="/home/buildroot/autobuild/run/instance-2/output-1/host/bin:/home/buildroot/autobuild/run/instance-2/output-1/host/sbin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games" ./configure.py --cpu="riscv32" --os=linux --cc=gcc --cc-bin="/home/buildroot/autobuild/run/instance-2/output-1/host/bin/riscv32-linux-g++" --prefix=/usr --without-documentation --extra-libs=atomic --disable-static-library --enable-shared-library --with-stack-protector --with-openssl --with-sqlite --with-zlib --disable-altivec --disable-neon)
   INFO: ./configure.py invoked with options "--cpu=riscv32 --os=linux --cc=gcc --cc-bin=/home/buildroot/autobuild/run/instance-2/output-1/host/bin/riscv32-linux-g++ --prefix=/usr --without-documentation --extra-libs=atomic --disable-static-library --enable-shared-library --with-stack-protector --with-openssl --with-sqlite --with-zlib --disable-altivec --disable-neon"
   INFO: Configuring to build Botan 2.17.3 (revision git:bcda19704da482c57eb0bce786cebb97f378f146)
   INFO: Running under 2.7.6 (default, Mar 22 2014, 22:59:56) [GCC 4.8.2]
   INFO: Autodetected platform information: OS="Linux" machine="x86_64" proc="x86_64"
   INFO: Using /etc/ssl/certs/ca-certificates.crt as system certificate store
  ERROR: Unknown or unidentifiable processor "riscv32"
make: *** [/home/buildroot/autobuild/run/instance-2/output-1/build/botan-2.17.3/.stamp_configured] Error 1
make: Leaving directory `/home/buildroot/autobuild/run/instance-2/buildroot'