qmake: let discard_from() discard function definitions as well

for completeness.

Change-Id: I3ffc14e041408c773e277442828170e3df04ec8d
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

qmake/library/qmakebuiltins.cpp

@@ -1365,6 +1365,18 @@ QMakeEvaluator::VisitReturn QMakeEvaluator::evaluateBuiltinConditional(
             }
             ++vit;
         }
+        for (auto fit = m_functionDefs.testFunctions.begin(); fit != m_functionDefs.testFunctions.end(); ) {
+            if (fit->pro() == pro)
+                fit = m_functionDefs.testFunctions.erase(fit);
+            else
+                ++fit;
+        }
+        for (auto fit = m_functionDefs.replaceFunctions.begin(); fit != m_functionDefs.replaceFunctions.end(); ) {
+            if (fit->pro() == pro)
+                fit = m_functionDefs.replaceFunctions.erase(fit);
+            else
+                ++fit;
+        }
         pro->deref();
         return ReturnTrue;
     }

tests/auto/tools/qmakelib/evaltest.cpp

@@ -2326,8 +2326,14 @@ void tst_qmakelib::addTestFunctions(const QString &qindir)
             << true;
 
     QTest::newRow("discard_from()")
-            << "HERE = 1\nPLUS = one\ninclude(include/inc.pri)\ndiscard_from(include/inc.pri): OK = 1"
+            << "HERE = 1\nPLUS = one\n"
-            << "OK = 1\nHERE = 1\nPLUS = one\nVAR = UNDEF"
+               "defineTest(tfunc) {}\ndefineReplace(rfunc) {}\n"
+               "include(include/inc.pri)\n"
+               "discard_from(include/inc.pri): OK = 1\n"
+               "defined(tfunc, test): TDEF = 1\ndefined(rfunc, replace): RDEF = 1\n"
+               "defined(func, test): DTDEF = 1\ndefined(func, replace): DRDEF = 1\n"
+            << "OK = 1\nHERE = 1\nPLUS = one\nVAR = UNDEF\n"
+               "TDEF = 1\nRDEF = 1\nDTDEF = UNDEF\nDRDEF = UNDEF"
             << ""
             << true;
 

tests/auto/tools/qmakelib/testdata/include/inc.pri

@@ -8,3 +8,7 @@ fake-*: MATCH = 1
 defineTest(func) {
     message("say hi!")
 }
+
+defineReplace(func) {
+    return("say hi!")
+}