Remove INT_MIN that came from the AST merge.

INT_MIN is used in Python/compile.c, but it was also used
in Objects/abstract.c Python/getargs.c.  If we need it for compile.c,
we can get it from the same place as the other files.

Include/pyport.h

@@ -583,7 +583,6 @@ typedef	struct fd_set {
 
 #ifndef INT_MAX
 #define INT_MAX 2147483647
-#define INT_MIN (-INT_MAX - 1)
 #endif
 
 #ifndef LONG_MAX