Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Includes/libc/locale.pxd

+# 7.11 Localization <locale.h>
+
+# deprecated cimport for backwards compatibility:
+from libc.string cimport const_char
+
+
+cdef extern from "locale.h" nogil:
+
+    struct lconv:
+        char *decimal_point
+        char *thousands_sep
+        char *grouping
+        char *mon_decimal_point
+        char *mon_thousands_sep
+        char *mon_grouping
+        char *positive_sign
+        char *negative_sign
+        char *currency_symbol
+        char frac_digits
+        char p_cs_precedes
+        char n_cs_precedes
+        char p_sep_by_space
+        char n_sep_by_space
+        char p_sign_posn
+        char n_sign_posn
+        char *int_curr_symbol
+        char int_frac_digits
+        char int_p_cs_precedes
+        char int_n_cs_precedes
+        char int_p_sep_by_space
+        char int_n_sep_by_space
+        char int_p_sign_posn
+        char int_n_sign_posn
+
+    enum: LC_ALL
+    enum: LC_COLLATE
+    enum: LC_CTYPE
+    enum: LC_MONETARY
+    enum: LC_NUMERIC
+    enum: LC_TIME
+
+    # 7.11.1 Locale control
+    char *setlocale (int category, const char *locale)
+
+    # 7.11.2 Numeric formatting convention inquiry
+    lconv *localeconv ()