CI: check new targets

.travis.yml

@@ -24,6 +24,14 @@ matrix:
       rust: nightly
       if: (branch = staging OR branch = trying OR branch = master) OR (type = pull_request AND branch = master)
 
+    - env: TARGET=riscv64imac-unknown-none-elf
+      rust: nightly
+      if: (branch = staging OR branch = trying OR branch = master) OR (type = pull_request AND branch = master)
+
+    - env: TARGET=riscv64gc-unknown-none-elf
+      rust: nightly
+      if: (branch = staging OR branch = trying OR branch = master) OR (type = pull_request AND branch = master)
+
     - env: TARGET=x86_64-unknown-linux-gnu
       rust: stable
       if: (branch = staging OR branch = trying OR branch = master) OR (type = pull_request AND branch = master)