simplify libtoolize detection

src/autogen.sh

@@ -4,15 +4,18 @@ set -x
 
 aclocal
 
-if test X"$HOMEBREW_ENV" != X; then
-    glt=`which glibtoolize`
-fi
-if test X"$glt" != X; then
-    $glt --copy
+# detect libtoolize on linux or glibtoolize in some systems
+if (libtoolize --version) < /dev/null > /dev/null 2>&1; then
+  LIBTOOLIZE=libtoolize
+elif (glibtoolize --version) < /dev/null > /dev/null 2>&1; then
+  LIBTOOLIZE=glibtoolize
 else
-    libtoolize --copy
+  echo "libtoolize or glibtoolize was not found! Please install libtool." 1>&2
+  exit 1
 fi
 
+$LIBTOOLIZE --copy
+
 automake --add-missing --force-missing --copy
 autoconf
 # Our ylwrap gets clobbered by the above.