Another attempt to get python config working multi platform

https://github.com/Hamlib/Hamlib/issues/477

macros/ax_python_devel.m4

@@ -149,7 +149,7 @@ variable to configure. See ``configure --help'' for reference.
         fi
     else
         sysconfig="sysconfig"
-        PYTHON_CPPFLAGS=`python3-config --cflags`
+        PYTHON_CPPFLAGS=`python3-config --includes`
         PYTHON_EXTRA_LDFLAGS=`python3-config --ldflags`
         AC_MSG_RESULT([yes])
     fi