Test: fixing itoa implementation and clean-up of tests and test Makefile (#8531)

* Test: fixing itoa implementation, clean-up of tests and test runner

Update itoa to be the same as newlib, fixing edgecase of abs(INT_MIN)
Update WString.cpp:toString() integer conversions to use noniso funcs
Remove legacy gcc versions from Makefile and allow overrides
Don't fallback to c11 and c++11, source cannot support that

* CXX and CC are make predefined values, assuming ?= does not work (?)

tests/host/common/ArduinoCatch.cpp

@@ -14,6 +14,25 @@
 */
 
 #define CATCH_CONFIG_MAIN
-#include <catch.hpp>
-#include <sys/time.h>
-#include "Arduino.h"
+#include "ArduinoCatch.hpp"
+
+std::ostream& operator<<(std::ostream& out, const String& str)
+{
+    out.write(str.c_str(), str.length());
+    return out;
+}
+
+namespace Catch
+{
+
+std::string toString(const String& str)
+{
+    return std::string(str.begin(), str.length());
+}
+
+std::string StringMaker<String>::convert(String const& str)
+{
+    return toString(str);
+}
+
+}  // namespace Catch

tests/host/common/ArduinoCatch.hpp

@@ -0,0 +1,36 @@
+/*
+ Arduino.cpp - Mocks for common Arduino APIs
+ Copyright © 2016 Ivan Grokhotkov
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+*/
+
+#include <Arduino.h>
+#include <sys/time.h>
+
+#include <ostream>
+
+#include "catch.hpp"
+
+// Since Catch does not know about Arduino types, help it out so we could have these displayed in the tests output
+
+std::ostream& operator<<(std::ostream&, const String&);
+
+namespace Catch {
+
+std::string toString(const String&);
+
+template<>
+struct StringMaker<String> {
+    static std::string convert(const String&);
+};
+
+} // namespace Catch

tests/host/common/noniso.c

@@ -65,29 +65,24 @@ char* itoa(int value, char* result, int base)
         *result = 0;
         return result;
     }
-    if (base != 10)
+
+    unsigned uvalue;
+    char*    out = result;
+
+    // after this point we convert the value to unsigned and go to the utoa
+    // only base10 gets minus sign in the front, adhering to the newlib implementation
+    if ((base == 10) && (value < 0))
     {
-        return utoa((unsigned)value, result, base);
+        *result++ = '-';
+        uvalue    = (unsigned)-value;
+    }
+    else
+    {
+        uvalue = (unsigned)value;
     }
 
-    char* out      = result;
-    int   quotient = abs(value);
-
-    do
-    {
-        const int tmp = quotient / base;
-        *out          = "0123456789abcdef"[quotient - (tmp * base)];
-        ++out;
-        quotient = tmp;
-    } while (quotient);
-
-    // Apply negative sign
-    if (value < 0)
-        *out++ = '-';
-
-    reverse(result, out);
-    *out = 0;
-    return result;
+    utoa(uvalue, result, base);
+    return out;
 }
 
 int atoi(const char* s)