Fix C reverse example for dfx 0.6.12. (dfinity#62)

Signed-off-by: John Plevyak <[email protected]>

c/reverse/README.adoc

@@ -20,19 +20,25 @@ wasm binary with:
 Then package the binary so `dfx` can install and run it:
 
   $ echo '{"canisters":{"reverse":{"main":"reverse"}}}' > dfx.json
-  $ mkdir build
-  $ mkdir build/reverse
-  $ cp reverse.wasm build/reverse/
-  $ head -c 8 /dev/urandom > build/reverse/_canister.id
 
 The script `build.sh` performs the above steps.
 
 To test the app, run `dfx start` in another terminal, then:
 
+  $ dfx canister create reverse
+  $ cp reverse.wasm .dfx/local/canisters/
   $ dfx canister install --all
-  $ dfx canister call reverse go --type string repaid
+  $ dfx canister call reverse go '("repaid")'
 
-Ignoring the error message about a missing ".did" file, we see:
+The script `start.sh` performs the above steps.
+
+We see:
 
   ("diaper")
 
+To stop and delete the canister:
+
+  $ dfx canister stop --all
+  $ dfx canister delete --all
+
+The script `stop.sh` performs the above steps.

c/reverse/build.sh

@@ -1,9 +1,7 @@
 #!/usr/bin/env bash
 set -e
-wld="wasm-ld-8 --no-entry --export-dynamic --allow-undefined"
-wcc="clang-8 --target=wasm32 -c -O3"
+wld="wasm-ld --no-entry --export-dynamic --allow-undefined"
+wcc="clang --target=wasm32 -c -O3"
 $wcc reverse.c
 $wld reverse.o -o reverse.wasm
 echo '{"canisters":{"reverse":{"main":"src/reverse"}}}' > dfx.json
-install -D reverse.wasm build/reverse/reverse.wasm
-head -c 8 /dev/urandom > build/reverse/_canister.id

c/reverse/start.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+set -e
+dfx canister create reverse
+cp reverse.wasm .dfx/local/canisters/
+dfx canister install --all
+dfx canister call reverse go '("repaid")'

motoko/echo/dfx.json

@@ -4,5 +4,5 @@
       "main": "src/main.mo"
     }
   },
-  "dfx": "0.6.10"
+  "dfx": "0.6.12"
 }