Update GNAT project for workarround Alire pin issues

Author: stcarrez

utilada_conf.gpr

@@ -16,6 +16,8 @@ abstract project UtilAda_Conf is
    --  Moved to UtilAda_Unit project but kept for Alire pins issues.
    type Unit_Type is ("none", "ahven-unix", "ahven-windows", "aunit");
 
+   Unit : Unit_Type := external ("UTIL_UNIT", "ahven-unix");
+
    type Asm_Version_Type is ("none", "intrinsic", "x86");
 
    Asm_Version : Asm_Version_Type := external ("UTIL_ASM_TYPE", "intrinsic");