slides/buildroot-appdev: improve pkg-config slide layout

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

slides/buildroot-appdev/buildroot-appdev.tex

@@ -53,7 +53,7 @@ \section{Application development}
 \begin{frame}[fragile]{Building code for Buildroot: pkg-config}
 
   \begin{block}{Using the system \code{pkg-config}}
-{\small
+{\scriptsize
 \begin{verbatim}
 $ pkg-config --cflags libpng
 -I/usr/include/libpng12
@@ -64,22 +64,18 @@ \section{Application development}
   \end{block}
 
   \begin{block}{Using the Buildroot \code{pkg-config}}
-{\small
+{\scriptsize
 \begin{verbatim}
 $ export PATH=$(pwd)/output/host/bin:$PATH
 
 $ pkg-config --cflags libpng
--I.../output/host/arm-buildroot-linux-uclibcgnueabi/
-    sysroot/usr/include/libpng16
+-I.../output/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/include/libpng16
 
 $ pkg-config --libs libpng
--L.../output/host/arm-buildroot-linux-uclibcgnueabi/
-    sysroot/usr/lib -lpng16
+-L.../output/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib -lpng16
 \end{verbatim}}
   \end{block}
 
-{\tiny Note: too long lines have been split.}
-
 \end{frame}
 
 \begin{frame}[fragile]{Building code for Buildroot: autotools}