Fix a couple of empty matches

---
 pygments/lexers/math.py |    2 +-
 pygments/lexers/web.py  |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

2 files changed, 2 insertions, 2 deletions

diff --git a/pygments/lexers/math.py b/pygments/lexers/math.py
index d69a8523..77067f35 100644
--- a/pygments/lexers/math.py
+++ b/pygments/lexers/math.py
@@ -668,7 +668,7 @@ class ScilabLexer(RegexLexer):
                             _scilab_builtins.macros_kw
                             ) + r')\b',  Name.Builtin),
 
-            ("(" + "|".join(_scilab_builtins.builtin_consts) + r')\b',
+            (r'(%s)\b' % "|".join(map(re.escape, _scilab_builtins.builtin_consts)),
              Name.Constant),
 
             # operators:
diff --git a/pygments/lexers/web.py b/pygments/lexers/web.py
index 1430e86a..6dc8c9b1 100644
--- a/pygments/lexers/web.py
+++ b/pygments/lexers/web.py
@@ -2617,7 +2617,7 @@ class XQueryLexer(ExtendedRegexLexer):
             (r'#\)', Punctuation, 'operator'),
             (ur'\t|\r|\n|[\u0020-\U0000D7FF]|[\U0000E000-\U0000FFFD]|'
              ur'[\U00010000-\U0010FFFF]', Literal),
-            (r'(\s*)', Text),
+            (r'(\s+)', Text),
         ],
         'occurrenceindicator': [
             include('whitespace'),