CMake: Add ENABLE_FUZZING and "afl" target

fuzzing/json.dict

@@ -0,0 +1,47 @@
+#
+# AFL dictionary for JSON
+# -----------------------------
+#
+
+object_start="{"
+object_end="}"
+object_empty="{}"
+object_one_element="{\"one\":1}"
+object_two_elements="{\"1\":1,\"2\":2}"
+object_separator=":"
+
+array_start="["
+array_end="]"
+array_empty="[]"
+array_one_element="[1]"
+array_two_elements="[1,2]"
+
+separator=","
+
+escape_sequence_b="\\b"
+escape_sequence_f="\\f"
+escape_sequence_n="\\n"
+escape_sequence_r="\\r"
+escape_sequence_t="\\t"
+escape_sequence_quote="\\\""
+escape_sequence_backslash="\\\\"
+escapce_sequence_slash="\\/"
+escpae_sequence_utf16_base="\\u"
+escape_sequence_utf16="\\u12ab"
+
+number_integer="1"
+number_double="1.0"
+number_negative_integer="-1"
+number_negative_double="-1.0"
+number_engineering1="1e1"
+number_engineering2="1e-1"
+number_positive_integer="+1"
+number_positive_double="+1.0"
+number_e="e"
+number_plus="+"
+number_minus="-"
+number_separator="."
+
+null="null"
+true="true"
+false="false"