[FE training-materials-updates] App dev lab: instruct to set pkg-config variables

[Michael Opdenacker]

Repository : git://git.free-electrons.com/training-materials.git

On branch  : master
Link       : http://git.free-electrons.com/training-materials/commit/?id=fb05076fb7684056645243242a62946309d723ee

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commit fb05076fb7684056645243242a62946309d723ee
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date:   Fri Mar 28 12:07:28 2014 +0100

    App dev lab: instruct to set pkg-config variables
    
    In this case, I believe we were not giving enough hints.
    (questions from users)
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>


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fb05076fb7684056645243242a62946309d723ee
 .../sysdev-application-development.tex             |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/labs/sysdev-application-development/sysdev-application-development.tex b/labs/sysdev-application-development/sysdev-application-development.tex
index 48d962c..2ddf8ba 100644
--- a/labs/sysdev-application-development/sysdev-application-development.tex
+++ b/labs/sysdev-application-development/sysdev-application-development.tex
@@ -49,7 +49,7 @@ It complains that it cannot find the directfb.h header. This is
 normal, since we didn't tell the compiler where to find it. So let's
 use \code{pkg-config} to query the {\em pkg-config} database about the
 location of the header files and the list of libraries needed to build
-an application against DirectFB:
+an application against DirectFB.
 
 \footnotesize
 \begin{verbatim}
@@ -57,7 +57,15 @@ arm-linux-gcc -o app app.c $(pkg-config --libs --cflags directfb)
 \end{verbatim}
 \normalsize
 
-Our application is now compiled! Copy the generated binary and the
+This will complain that it cannot find the \code{pkg-config} files. It's
+because we didn't set the \code{PKG_CONFIG_SYSROOT_DIR} and
+\code{PKG_CONFIG_PATH} environment variables to specify where the
+\code{pkg-config} database is. So find the location of the \code{directfb.pc} 
+file and specify the above two variables accordingly.
+
+Run the compiler command again.
+
+Our application should now be compiled! Copy the generated binary and the
 \code{background.png} image to the NFS root filesystem (in the
 \code{root/} directory for example), start your system, and run your
 application!