Travis: run PPC builds

.travis.yml

@@ -26,8 +26,16 @@ script:
  - ./configure --disable-dependency-tracking --enable-minimal
  - make check
  - ( echo '#include <sodium.h>' ; echo 'int main(void) { return sodium_init(); }' ) > /tmp/main.c && gcc -Isrc/libsodium/include -Isrc/libsodium/include/sodium $(find src -name '*.c' -o -name '*.S') /tmp/main.c
+ - make distclean > /dev/null
+
+after_success:
+ - ./configure --disable-dependency-tracking --host=powerpc-linux-gnu
+ - env QEMU_LD_PREFIX=/usr/powerpc-linux-gnu make -j $(nproc) check
+ - make clean > /dev/null
 
 addons:
   apt:
     packages:
       - tcc
+      - qemu-user-static
+      - gcc-powerpc-linux-gnu