Check python installed in autogen.sh

python is required to build fontconfig from the scratch
diff --git a/autogen.sh b/autogen.sh
index 40751ee..07c59a4 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -47,6 +47,7 @@
 AUTOHEADER=${AUTOHEADER-autoheader}
 AUTOCONF=${AUTOCONF-autoconf}
 GPERF=${GPERF-gperf}
+PYTHON=${PYTHON-python}
 LIBTOOLIZE_FLAGS="--copy --force"
 
 DIE=0
@@ -59,6 +60,14 @@
 	DIE=1
 }
 
+($PYTHON --version) < /dev/null > /dev/null 2>&1 || {
+	echo
+	echo "You must have python installed to compile $PROJECT."
+	echo "Install the appropriate package for your distribution."
+	echo "or get the source tarball at https://www.python.org/downloads/source/"
+	DIE=1
+}
+
 have_libtool=false
 if $LIBTOOLIZE --version < /dev/null > /dev/null 2>&1 ; then
 	libtool_version=`$LIBTOOLIZE --version | sed 's/^.* \([0-9][.][0-9.]*\)[^ ]*$/\1/'`