Fix cmake setup for yocto

[GertRozing]

The current cmake setup of the pigpio project was incompatible with a yocto build for the raspberry pi. For some reason it had problems finding standard header files like <stdio.h>. However the builds succeeded on non Yocto builds which reinforced my suspicion that the CMake setup was the cause.

Nevertheless I modernized the CMake setup, which now also builds in a yocto environment :D. The new CMake conforms with the current CMake 3.0 standard. As such the following features are available.

• Usage of CMAKE_INSTALL_PREFIX instead of the custom DEST_DIR
• Usage of CMAKE_BUILD_TYPE to determine Release/Debug or RelWithDebInfo builds.
• Usage of CMake versioning system
• Create a CMake importable package configuration for all configurations.
• Create a CMake installer via CPack (build the package target)
• Usage of dependency handling via CMake target architecture (no more add_dependencies)
• Finding of external dependencies via CMake (CMake will raise an error if -lpthread or -lrt are not present on the system)
• Moved the option like option (BUILD_SHARED_LIBS) to an actual option (default is ON).
• Removed the uninstall target (CMake tracks all install commands and provides an uninstall target, however this is not compatible with the custom python module setup.py)

I wrote these enhancements for our own raspberry pi yocto builds, which require pigpio. We used to use WiringPi, however that project got disbanded by the maintainer himself, which is sad. Nevertheless the pigpio project works equally amazing.

[joan2937]

I have no knowledge or experience of using cmake so can not judge the merits of this request.

That said, I am happy to accept this as long as no one objects within a few days.

[deets]

I would like to second this issue, I was hunting down this for a couple of hours today for my own yocto build until I solved it myself with a patch. It would be great if this was merged.

[guymcswain]

I'll try to include this in the next release sometime in March.

[novalisek]

@GertRozing Do you have pigpio recipe which works with this PR? coud you share it? I would like to add pigpio to my yocto build. Thank you.

[dir-ableton]

I have this recipe. It comes with it's own patch to prevent the issue here, but you can now of course just ditch that. It is also not very sophisticated, but it gets you going.

DESCRIPTION = "pigpio "
SECTION = "devtools"
LICENSE = "CLOSED"
LIC_FILES_CHKSUM = "file://UNLICENCE"

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"

SRC_URI = "git://github.com/joan2937/pigpio.git;protocol=https;tag=${PV}\
    file://0001-Fix-CFLAGS-so-cross-compilation-in-YOCTO-works.patch\
    file://pigpiod.sh\
    "

S = "${WORKDIR}/git"

inherit pkgconfig cmake update-rc.d

RDEPENDS_${PN} = "python3"

FILES_${PN} += "${bindir}/pigpiod\
    ${libdir}/libpigpio.so\
    ${libdir}/libpigpiod_if.so\
    ${libdir}/libpigpiod_if2.so\
    ${libdir}/python3.7/site-packages/pigpio.py\
"

FILES_${PN}-dev = "${includedir}"

INITSCRIPT_NAME = "pigpiod"
INITSCRIPT_PARAMS = "start 01 5 3 2 . stop 99 0 1 6 ."

do_install() {
    install -d ${D}${bindir}
    install -d ${D}${libdir}
    install -d ${D}${libdir}/python3.7/site-packages

    install -m 0755 pigpiod ${D}${bindir}
    install -m 0755 libpigpio.so ${D}${libdir}
    install -m 0755 libpigpiod_if.so ${D}${libdir}
    install -m 0755 libpigpiod_if2.so ${D}${libdir}
    install -m 0644 ${S}/pigpio.py ${D}${libdir}/python3.7/site-packages

    install -d ${D}${sysconfdir}/init.d
    install -m 0755 ${WORKDIR}/pigpiod.sh ${D}${sysconfdir}/init.d/pigpiod
}

[novalisek]

@dir-ableton thanks, I will give it a try