makefile

I have a Makefile.am setup much like what follows in order to compile MOC files for Qt using Autotools. I think it may have something to do with not finding the headers as they are located outside of the directory which is compiling the cpp files.

---
bin_PROGRAMS = test

test_qtheaders = window.h

test_moc_sources = $(test_qtheaders:.h=_moc.cpp)

test_SOURCES =               \
    main.cpp                 \
    main-window.cpp          \
    window.cpp               \
    $(test_moc_sources)

test_CPPFLAGS = -I/usr/include -I/usr/local/include -I$(QT5_INCL) -I$(QT5_INCL)/QtWidgets -I$(QT5_INCL)/QtCore

test_LDFLAGS = -L/usr/lib64 -L/usr/local/lib64 -L/usr/local/lib -L$(QT5_LIBS)

test_LDADD = -lrt -lQt5Core -lQt5Gui -lQt5Widgets

SUFFIXES = .h _moc.cpp

# problem here, not able to find where the *.h file is as it's not in the current directory.
.h_moc.cpp:
    $(QT_MOC) -o $@ $(test_CPPFLAGS) $(CPPFLAGS) $<
---
I get the following error.
make[4]: *** No rule to make target 'window_moc.cpp', needed by 'test-window_moc.o'.  Stop.

My directory structure appears as follows:

myproj
|- configure.ac
|- Makefile.am
|- ...
` src
    |- Makefile.am
    |- includes
    |    `- gui
    |        |- main-window.h
    |        `- window.h    // MOC source file used to generate *.cpp.
    |
    `- gui
        |- Makefile.am
        |- main.cpp
        |- main-window.cpp
        `- window.cpp   // MOC file yet to be generated, does not yet exist before build.