respect tristate return values from isinf() functions instead of shadowing...

respect tristate return values from isinf() functions instead of shadowing them in a "bint" declaration

Cython/Includes/libc/math.pxd

@@ -96,8 +96,8 @@ cdef extern from "math.h" nogil:
 
     double nan(const char*)
 
+    int isinf(long double)   # -1 / 0 / 1
     bint isfinite(long double)
-    bint isinf(long double)
     bint isnan(long double)
     bint isnormal(long double)
     bint signbit(long double)

Cython/Includes/numpy/math.pxd

@@ -25,8 +25,8 @@ cdef extern from "numpy/npy_math.h" nogil:
     long double NZERO "NPY_NZERO"        # negative zero
 
     # These four are actually macros and work on any floating-point type.
+    int isinf "npy_isinf"(long double)  # -1 / 0 / 1
     bint isfinite "npy_isfinite"(long double)
-    bint isinf "npy_isinf"(long double)
     bint isnan "npy_isnan"(long double)
     bint signbit "npy_signbit"(long double)