Prevent infinite recursion

In qtvirtualkeyboard/src/plugins/lipi-toolkit/3rdparty/lipi-toolkit/src/lipicommon.pri
we have TARGET = $$TARGET$$qtPlatformTargetSuffix which keeps on recursing.

Change-Id: Ia0e020c7258cd87bba9b9681ed7b4568e8f0c9c2
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

util/cmake/pro2cmake.py

@@ -1111,6 +1111,9 @@ class Scope(object):
             else:
                 replacement = self.get(match.group(1), inherit=True)
                 replacement_str = replacement[0] if replacement else ""
+                if replacement_str == value:
+                    # we have recursed
+                    replacement_str = ""
                 result = result[: match.start()] + replacement_str + result[match.end() :]
                 result = self._replace_env_var_value(result)