.
Sigo mirando cosas, a mi la vía de acceso al mkspecs que comenta ferzone82, no me sale. Y algo que es importante, hay que fijar la vía al mkspecs correspondiente al Raspberry Pi3. Si no se hace así, el producto puede compilar, pero el objeto resultante no funcionará en un Raspeberry Pi3.
En el mkspecs correspondiente, hay un fichero qmake.conf que define toda la parametrización necesaria para la compilación. En el caso del Raspberry Pi3, este qmake.conf está en un subdirectorio con el nombre linux-rpi3-g++. Asi que la vía de acceso CORRECTA del mkspecs, para compilar para Raspberry Pi3, debe de apuntar a ese subdirectorio.
En ese subdirectorio nos encontraremos un fichero qmake.conf con este contenido.
# qmake configuration for the Raspberry Pi 3 using the Broadcom graphics stack
include(../common/linux_device_pre.conf)
# For modern Yocto-based sysroots that have the proper include and lib
# setup in egl.pc we will pull the necessary arguments from
# there. However, to support Raspbian and older stuff that has /opt/vc
# and possibly no pkg-config, have some static values as well:
# I consider it a bug that this is required, but our EGL config.test _requires_ it
QMAKE_LFLAGS += -L$${VC_LIBRARY_PATH}
VC_LIBRARY_PATH = $$[QT_SYSROOT]/opt/vc/lib
VC_INCLUDE_PATH = $$[QT_SYSROOT]/opt/vc/include
# terrible, they do not appear to resolve "=" in rpath!
VC_LINK_LINE = -L$${VC_LIBRARY_PATH}
QMAKE_LIBDIR_OPENGL_ES2 = =$${VC_LIBRARY_PATH}
QMAKE_LIBDIR_EGL = $$QMAKE_LIBDIR_OPENGL_ES2
QMAKE_LIBDIR_OPENVG = $$QMAKE_LIBDIR_OPENGL_ES2
QMAKE_INCDIR_EGL = \
$${VC_INCLUDE_PATH} \
$${VC_INCLUDE_PATH}/interface/vcos/pthreads \
$${VC_INCLUDE_PATH}/interface/vmcs_host/linux
QMAKE_INCDIR_OPENGL_ES2 = $${QMAKE_INCDIR_EGL}
QMAKE_LIBS_OPENGL_ES2 = $${VC_LINK_LINE} -lGLESv2
# The official opt vc EGL references GLESv2 symbols: need to link it
QMAKE_LIBS_EGL = $${VC_LINK_LINE} -lEGL -lGLESv2
QMAKE_CFLAGS = -march=armv8-a -mtune=cortex-a53 -mfpu=crypto-neon-fp-armv8
QMAKE_CXXFLAGS = $$QMAKE_CFLAGS
DISTRO_OPTS += hard-float
DISTRO_OPTS += deb-multi-arch
EGLFS_DEVICE_INTEGRATION= eglfs_brcm
include(../common/linux_arm_device_post.conf)
load(qt_config)
También nos encontraremos el fichero qplatformdefs.h, con este contenido.
/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the qmake spec of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "../../linux-g++/qplatformdefs.h"
