HostOsInfo: Add some more useful abstractions.

Namely:
- path list separator
- executable suffix
- file name case sensitivity

All of these are duplicated in various places in the current Creator
code.

Change-Id: I86eb4662fa3c2071759bd728cae1aaf7111ae686
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>

src/plugins/qnx/blackberryqtversion.cpp

@@ -73,8 +73,8 @@ QMultiMap<QString, QString> parseEnvironmentFile(const QString &fileName)
     QMapIterator<QString, QString> it(fileContent);
     while (it.hasNext()) {
         it.next();
-        const QChar sep = Utils::HostOsInfo::isWindowsHost() ? QLatin1Char(';') : QLatin1Char(':');
-        const QStringList values = it.value().split(sep);
+        const QStringList values
+                = it.value().split(Utils::HostOsInfo::pathListSeparator());
         QString key = it.key();
         foreach (const QString &value, values) {
             const QString ownKeyAsWindowsVar = QLatin1Char('%') + key + QLatin1Char('%');