Consult tput about color control sequence support

Blocking these sequences on Darwin has false positives (Terminal.app)
and false negatives (Eclipse CDT on Linux).  Instead let's ask the
terminal what it supports.

Change-Id: I907942925a8b30abc1ea920f077b5fc3af815ba4
Signed-off-by: Greg Hackmann <ghackmann@google.com>

envsetup.sh

@@ -1651,19 +1651,21 @@ function make()
     local hours=$(($tdiff / 3600 ))
     local mins=$((($tdiff % 3600) / 60))
     local secs=$(($tdiff % 60))
+    local ncolors=$(tput colors 2>/dev/null)
+    if [ -n "$ncolors" ] && [ $ncolors -ge 8 ]; then
+        color_failed="\e[0;31m"
+        color_success="\e[0;32m"
+        color_reset="\e[00m"
+    else
+        color_failed=""
+        color_success=""
+        color_reset=""
+    fi
     echo
     if [ $ret -eq 0 ] ; then
-        if [ $(uname) != "Darwin" ]; then
-            echo -n -e "\e[0;32m#### make completed successfully "
-        else
-            echo -n -e "#### make completed successfully "
-        fi
+        echo -n -e "${color_success}#### make completed successfully "
     else
-        if [ $(uname) != "Darwin" ]; then
-            echo -n -e "\e[0;31m#### make failed to build some targets "
-        else
-            echo -n -e "#### make failed to build some targets "
-        fi
+        echo -n -e "${color_failed}#### make failed to build some targets "
     fi
     if [ $hours -gt 0 ] ; then
         printf "(%02g:%02g:%02g (hh:mm:ss))" $hours $mins $secs
@@ -1672,9 +1674,7 @@ function make()
     elif [ $secs -gt 0 ] ; then
         printf "(%s seconds)" $secs
     fi
-    if [ $(uname) != "Darwin" ]; then
-        echo -e " ####\e[00m"
-    fi
+    echo -e " ####${color_reset}"
     echo
     return $ret
 }