Fix building this library with GNAT GPL 2017

Makefile

@@ -34,7 +34,9 @@ test: build install build_driver
 
 # Driver only needs to be recompiled when the step definitions change
 build_driver: 
+# Build example/obj/driver.adb
 	${bindir}/gnatbdd -Pexample/calc.gpr
+# Compile this driver
 	GPR_PROJECT_PATH=${projectdir} ${GPRBUILD} -P example/obj/driver.gpr
 
 force:

README.md

@@ -11,3 +11,7 @@ the code until the tests pass.
 See the documentation at:
 
    http://briot.github.com/gnatbdd/
+
+To get started and run a simple example, execute
+
+   make test

example/features/step_definitions/mysteps1.adb

@@ -11,7 +11,7 @@ package body MySteps1 is
 
    procedure Then_I_Should_Read (Result : Integer) is
    begin
-      Assert (Result, Peek);
+      Assert_Equal (Result, Peek);
    end Then_I_Should_Read;
 
    procedure Then_The_Stack_Should_Contain (Expected : BDD.Tables.Table) is

gnatbdd_main.gpr

@@ -9,7 +9,7 @@ project GNATBDD_Main is
 
    package Compiler is
       for Switches ("Ada") use ("-g", "-gnata", "-gnatVa", "-gnatQ",
-                                "-gnatyg0", "-gnatwaCJe", "-gnat2012",
+                                "-gnatyg0", "-gnatwaCJ", "-gnat2012",
                                 "-gnateE");
    end Compiler;