Consider the following .pro file:

TEMPLATE = lib
CONFIG += staticlib
DESTDIR = foo
TARGET= bar

The actual result of running qmake on this .pro file results in the following Makefile contents:

...
DESTDIR = foo/
TARGET = libbar.a
...
distclean: clean
-$(DEL_FILE) $(TARGET)
-$(DEL_FILE) Makefile
...

However, the expected distclean rule is:

distclean: clean
-$(DEL_FILE) foo/$(TARGET)
-$(DEL_FILE) Makefile