Trying to install the latest GtkAda for Mac on Mojave using Community 2018

[ahlan@marriott.org]

Once upon a time, (2015), I successfully installed GtkAda 3.8.4 using Macports and then GtkAda from the sources provided in gtkada-gpl-2015-src.tar.gz and all was well.

However on buying a new Mac I tried to do the same thing but failed.
As I don't particularly want to remain on this version I have tried to install the latest and greatest.

But again without success.
Can someone give me a clue as to what I am doing wrong or what I should be doing.
Is there a better way of getting GtkAda running on my MAC?

I  installed the community 2018 version of GNAT for OSX.
Easy - so far so good.

I assume that GtkAda needs Gtk3 for Quartz and so I installed Macports 2.5.3 and then did a port install of gtk3 +quartz which installed 3.22.30
So far so good.

I then cloned the sources for GtkAda from GitHub.com/AdaCore/gtkada and then tried to build GtkAda.

Previously I changed directory to the sources and then entered

CC=/usr/bin/gcc ./configure --prefix=/Users/Ahlan/gtkada
make
make install

However the make now fails when trying to compile misc.c on line 32 
#include <stdio.h>
fatal error: stdio.h: No such file

and misc_generated.c fails to find limits.h

How is it supposed to find these files?
Do I need to install something else?
Am I installing GtkAda in the correct and recommended manner?

Any help very much appreciated.
Best wishes,
Ahlan