[yocto] Missing dependencies in recipe-sysroot

[Burton, Ross]

We've already gone through this on SO but I'll copy/paste here.

On Tue, 4 Dec 2018 at 08:30, Georgi Georgiev
<Georgi.Georgiev at woodward.com> wrote:
> #####The only dependency
>
> RDEPENDS_${PN} = "libgpiod"
>
> RDEPENDS_${PN}-dev = "libgpiod"
>
> RDEPENDS_${PN}-dbg = "libgpiod"

DEPENDS = "libgpiod".  RDEPENDS will build libgpiod at some point, but
it won't be in the sysroot for compilation.  Before
recipe-specific-sysroots this would mean it *might* be present, now it
reliably won't.

> Then I noticed that the command line is:
>
> arm-poky-linux-gnueabi-gcc  -march=armv7-a -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a9 --sysroot=/<full path>/recipe-sysroot -L/usr/lib -g -Wall -fpic .....

The problem is the -L/usr/lib, which presumably should be where
libgpiod is.  The makefile is broken, or possibly some tooling that
the makefile is calling.  As you haven't shared the makefile we can't
help further.

Ross