dependencies: add perl as a mandatory dependency

Now that we might happen to build libxml-parser-perl and intltool,
Perl becomes a mandatory dependency. This shouldn't be a problem since
most distributions install Perl by default anyway.

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

toolchain/dependencies/dependencies.sh

@@ -122,7 +122,7 @@ if ! $SHELL --version 2>&1 | grep -q '^GNU bash'; then
 fi;
 
 # Check that a few mandatory programs are installed
-for prog in awk bison flex msgfmt makeinfo patch gzip bzip2 ; do
+for prog in awk bison flex msgfmt makeinfo patch gzip bzip2 perl ; do
     if ! which $prog > /dev/null ; then
 	/bin/echo -e "\nYou must install '$prog' on your build machine";
 	if test $prog = "makeinfo" ; then