bc: fix comment handling

function                                             old     new   delta
bc_vm_run                                            514     513      -1

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

testsuite/bc.tests

@@ -4,6 +4,18 @@
 
 . ./testing.sh
 
+# testing "test name" "command" "expected result" "file input" "stdin"
+
+testing "bc comment 1" \
+	"bc" \
+	"3\n" \
+	"" "1 /* comment */ + 2"
+
+testing "bc comment 2: /*/ is not a closed comment" \
+	"bc" \
+	"4\n" \
+	"" "1 /*/ + 2 */ + 3"
+
 tar xJf bc_large.tar.xz
 
 for f in bc*.bc; do