Updated build.sh and test.sh to fail more gracefully

when Menhir or MenhirLib cannot be built or installed.

quicktest/build.sh

@@ -24,5 +24,10 @@ fi
 
 # Re-install MenhirLib.
 ocamlfind remove menhirLib
-ocamlfind install menhirLib $SRC/META $BUILD/menhirLib.cmi $BUILD/menhirLib.cmo $BUILD/menhirLib.cmx $BUILD/menhirLib.o
+if ! ocamlfind install menhirLib \
+  $SRC/META $BUILD/menhirLib.cmi $BUILD/menhirLib.cmo \
+  $BUILD/menhirLib.cmx $BUILD/menhirLib.o ; then
+  echo "Could not install MenhirLib. Stop."
+  exit 1
+fi
 

quicktest/test.sh

@@ -7,7 +7,7 @@
 . ./config.sh
 
 # Make sure Menhir and MenhirLib are up-to-date.
-./build.sh
+./build.sh || exit 1
 
 # Build the parser with the code back-end and run it.
 echo "Building and running (code)..."