extract C macro into utility code file

Cython/Compiler/ExprNodes.py

@@ -9839,7 +9839,7 @@ class DivNode(NumBinopNode):
                 code.putln(code.error_goto(self.pos))
                 code.putln("}")
                 if self.type.is_int and self.type.signed and self.operator != '%':
-                    code.globalstate.use_utility_code(division_overflow_test_code)
+                    code.globalstate.use_utility_code(UtilityCode.load_cached("UnaryNegOverflows", "Overflow.c"))
                     if self.operand2.type.signed == 2:
                         # explicitly signed, no runtime check needed
                         minus1_check = 'unlikely(%s == -1)' % self.operand2.result()
@@ -11903,10 +11903,3 @@ static int __Pyx_cdivision_warning(const char *filename, int lineno) {
 #endif
 }
 """)
-
-# from intobject.c
-division_overflow_test_code = UtilityCode(
-proto="""
-#define UNARY_NEG_WOULD_OVERFLOW(x)    \
-        (((x) < 0) & ((unsigned long)(x) == 0-(unsigned long)(x)))
-""")

Cython/Utility/Overflow.c

@@ -282,3 +282,10 @@ static CYTHON_INLINE {{TYPE}} __Pyx_lshift_{{NAME}}_checking_overflow({{TYPE}} a
 }
 #define __Pyx_lshift_const_{{NAME}}_checking_overflow __Pyx_lshift_{{NAME}}_checking_overflow
 
+
+/////////////// UnaryNegOverflows.proto ///////////////
+
+//FIXME: shouldn't the macro name be prefixed by "__Pyx_" ?  Too late now, I guess...
+// from intobject.c
+#define UNARY_NEG_WOULD_OVERFLOW(x)    \
+        (((x) < 0) & ((unsigned long)(x) == 0-(unsigned long)(x)))