.gitignore: don't ignore sources, do ignore CMake build/

.gitignore

@@ -32,7 +32,6 @@ src-qt5/desktop-utils/lumina-archiver/lumina-archiver
 src-qt5/desktop-utils/lumina-calculator/lumina-calculator
 src-qt5/desktop-utils/lumina-pdf/lumina-pdf
 src-qt5/desktop-utils/lumina-notify/lumina-notify
-src-qt5/core/lumina-theme-engine/src/lthemeengine-qtplugin/
 src-qt5/core/lumina-theme-engine/src/lthemeengine-qtplugin/Makefile
 src-qt5/core/lumina-theme-engine/src/lthemeengine-qtplugin/liblthemeengine.so
 src-qt5/core/lumina-theme-engine/src/lthemeengine-sstest/Makefile
@@ -58,3 +57,6 @@ icon-theme/*/Makefile
 ./Makefile
 src-qt5/src-qml/test/*
 src-qt5/desktop-utils/lumina-pdf/fontconfig/*
+
+# CMake-build parts
+src-qt5/core/build/