diff -ru pycparser-release_v2.14/pycparser/c_lexer.py pycparser-release_v2.14_patched/pycparser/c_lexer.py
--- pycparser-release_v2.14/pycparser/c_lexer.py	2019-06-06 15:51:41.937286040 +0200
+++ pycparser-release_v2.14_patched/pycparser/c_lexer.py	2019-06-06 15:53:15.269120067 +0200
@@ -52,8 +52,8 @@
         # Allow either "# line" or "# <num>" to support GCC's
         # cpp output
         #
-        self.line_pattern = re.compile('([ \t]*line\W)|([ \t]*\d+)')
-        self.pragma_pattern = re.compile('[ \t]*pragma\W')
+        self.line_pattern = re.compile(r'([ \t]*line\W)|([ \t]*\d+)')
+        self.pragma_pattern = re.compile(r'[ \t]*pragma\W')
 
     def build(self, **kwargs):
         """ Builds the lexer from the specification. Must be
diff -ru pycparser-release_v2.14/pycparser/c_lexer.py.ply pycparser-release_v2.14_patched/pycparser/c_lexer.py.ply
--- pycparser-release_v2.14/pycparser/c_lexer.py.ply	2015-06-10 05:00:55.000000000 +0200
+++ pycparser-release_v2.14_patched/pycparser/c_lexer.py.ply	2019-06-06 15:53:44.972385501 +0200
@@ -52,8 +52,8 @@
         # Allow either "# line" or "# <num>" to support GCC's
         # cpp output
         #
-        self.line_pattern = re.compile('([ \t]*line\W)|([ \t]*\d+)')
-        self.pragma_pattern = re.compile('[ \t]*pragma\W')
+        self.line_pattern = re.compile(r'([ \t]*line\W)|([ \t]*\d+)')
+        self.pragma_pattern = re.compile(r'[ \t]*pragma\W')
 
     def build(self, **kwargs):
         """ Builds the lexer from the specification. Must be
diff -ru pycparser-release_v2.14/tests/test_c_lexer.py pycparser-release_v2.14_patched/tests/test_c_lexer.py
--- pycparser-release_v2.14/tests/test_c_lexer.py	2015-06-10 05:00:55.000000000 +0200
+++ pycparser-release_v2.14_patched/tests/test_c_lexer.py	2019-06-10 14:57:24.981643354 +0200
@@ -403,12 +403,12 @@
         self.assertLexerError("'b\n", ERR_UNMATCHED_QUOTE)
 
         self.assertLexerError("'jx'", ERR_INVALID_CCONST)
-        self.assertLexerError("'\*'", ERR_INVALID_CCONST)
+        self.assertLexerError(r"'\*'", ERR_INVALID_CCONST)
 
     def test_string_literals(self):
-        self.assertLexerError('"jx\9"', ERR_STRING_ESCAPE)
-        self.assertLexerError('"hekllo\* on ix"', ERR_STRING_ESCAPE)
-        self.assertLexerError('L"hekllo\* on ix"', ERR_STRING_ESCAPE)
+        self.assertLexerError(r'"jx\9"', ERR_STRING_ESCAPE)
+        self.assertLexerError(r'"hekllo\* on ix"', ERR_STRING_ESCAPE)
+        self.assertLexerError(r'L"hekllo\* on ix"', ERR_STRING_ESCAPE)
 
     def test_preprocessor(self):
         self.assertLexerError('#line "ka"', ERR_FILENAME_BEFORE_LINE)
diff -ru pycparser-release_v2.14/tests/test_c_parser.py pycparser-release_v2.14_patched/tests/test_c_parser.py
--- pycparser-release_v2.14/tests/test_c_parser.py	2015-06-10 05:00:55.000000000 +0200
+++ pycparser-release_v2.14_patched/tests/test_c_parser.py	2019-06-10 14:58:40.725330566 +0200
@@ -1637,7 +1637,7 @@
 
         self.assertTrue(isinstance(p.ext[0], Typedef))
         self.assertEqual(p.ext[0].coord.line, 213)
-        self.assertEqual(p.ext[0].coord.file, "D:\eli\cpp_stuff\libc_include/stddef.h")
+        self.assertEqual(p.ext[0].coord.file, r"D:\eli\cpp_stuff\libc_include/stddef.h")
 
         self.assertTrue(isinstance(p.ext[-1], FuncDef))
         self.assertEqual(p.ext[-1].coord.line, 15)