--- a/src/src.pro	Sun Aug 11 03:47:58 2013 +0300
+++ b/src/src.pro	Sun Aug 11 13:33:57 2013 +0300
@@ -9,6 +9,9 @@
 RCC_DIR         = ./build/
 SOURCES         = *.cpp
 HEADERS         = *.h
-QT             += widgets
 FORMS           = ui/*.ui
-QMAKE_CXXFLAGS += -std=c++0x
\ No newline at end of file
+QMAKE_CXXFLAGS += -std=c++0x
+
+# The widgets are separated into a different module in Qt5, so we need to add
+# it here. Doing so under Qt4 just results in a warning, though.
+greaterThan (QT_MAJOR_VERSION, 4): QT += widgets
\ No newline at end of file