Added regex support as per issue #164.

jq now depends on oniguruma for regex support.
Modified configure.ac accordingly.

Added valgrind suppression file for oniguruma to prevent one-time and bounded
leaks from causing tests to fail.

Signed-off-by: Nicolas Williams <nico@cryptonector.com>

docs/content/3.manual/manual.yml

@@ -1087,6 +1087,78 @@ sections:
             input: '["foobar", "barfoo"]'
             output: ['[false, true, true, false, false]']
 
+      - title: "`match(val)`, `match(regex; modifiers)`"
+        body: |
+
+          The filter `match(val)` performs PCRE regex matching on its input.
+          `val` can be either a string or an array.  If it is an array, 
+          the first element is the regex specifier and the optional
+          second element is the modifier flags.
+          The accepted modifier flags are:
+          
+          * `g` - Global search (find all matches, not just the first)
+          * `i` - Case insensitive search
+          * `x` - Extended regex format (ignore whitespaces)
+          * `m` - Multi line mode ('.' will match newlines)
+          * `s` - Single line mode ('^' -> '\A', '$' -> '\Z')
+          * `p` - Both s and m modes are enabled
+          * `l` - Find longest possible matches
+          * `n` - Ignore empty matches
+          
+          The filter outputs an object for each match it finds.  Matches have
+          the following fields:
+          
+          * `offset` - offset in UTF-8 codepoints from the beginning of the input
+          * `length` - length in UTF-8 codepoints of the match
+          * `string` - the string that it matched
+          * `captures` - an array of objects representing capturing groups.
+          
+          Capturing group objects have the following fields:
+          
+          * `offset` - offset in UTF-8 codepoints from the beginning of the input
+          * `length` - length in UTF-8 codepoints of this capturing group
+          * `string` - the string that was captured
+          * `name` - the name of the capturing group (or `null` if it was unnamed)
+
+          Capturing groups that did not match anything return an offset of -1
+
+        examples:
+          - program: 'match("(abc)+"; "g")'
+            input: '"abc abc"'
+            output: 
+             - '{"offset": 0, "length": 3, "string": "abc", "captures": [{"offset": 0, "length": 3, "string": "abc", "name": null}]}'
+             - '{"offset": 4, "length": 3, "string": "abc", "captures": [{"offset": 4, "length": 3, "string": "abc", "name": null}]}'
+          - program: 'match("foo")'
+            input: '"foo bar foo"'
+            output: ['{"offset": 0, "length": 3, "string": "foo", "captures": []}']
+          - program: 'match(["foo", "ig"])'
+            input: '"foo bar FOO"'
+            output: 
+             - '{"offset": 0, "length": 3, "string": "foo", "captures": []}'
+             - '{"offset": 8, "length": 3, "string": "FOO", "captures": []}'
+          - program: 'match("foo (?<bar123>bar)? foo"; "ig")'
+            input: '"foo bar foo foo  foo"'
+            output:
+             - '{"offset": 0, "length": 11, "string": "foo bar foo", "captures": [{"offset": 4, "length": 3, "string": "bar", "name": "bar123"}]}'
+             - '{"offset": 12, "length": 8, "string": "foo  foo", "captures": [{"offset": -1, "length": 0, "string": null, "name": "bar123"}]}'
+
+
+      - title: "`test(val)`, `test(regex)`, `test(regex; modifiers)`"
+        body: |
+
+           Like `match`, but does not return match objects, only `true` or `false`
+           for whether or not the regex matches the input.
+
+        examples:
+         - program: 'test("foo")'
+           input: '"foo"'
+           output: ['true']
+         - program: 'test("foo"; "i")'
+           input: '"Foo"'
+           output: ['true']
+         - program: 'test("foo")'
+           input: '"bar"'
+           output: ['false']
       - title: "`ltrimstr(str)`"
         body: |