install-tools: Fix install error

Newer Ubuntu versions don't include libncurses5, so the installation
is failed. This commit checks whether the specified library versions
are available and attempts to install the required ones separately.

install-tools.sh

@@ -97,10 +97,12 @@ run_progress()
 
 linux_install_tools()
 {
-    local _packages="git gperf libncurses5 libncurses5-dev flex bison genromfs pkg-config autoconf automake curl make minicom unzip"
+    local _packages="git gperf libncurses5 libncurses6 libncurses5-dev libncurses-dev flex bison genromfs pkg-config autoconf automake curl make minicom unzip"
     local _needed
     for p in ${_packages}; do
-        dpkg -s $p >/dev/null 2>&1 || _needed="${_needed} ${p}"
+        if LANG=C apt-cache policy $p | grep -q "Candidate:"; then
+            dpkg -s $p >/dev/null 2>&1 || _needed="${_needed} ${p}"
+        fi
     done
 
     if [ -n "${_needed}" ]; then