[PATCH 2 of 8] Added new root prefixes option

[Per Olav Høydahl Ohme]

# HG changeset patch
# User Per Olav Hoydahl Ohme <phoydahl at cisco.com>
# Date 1405683324 -7200
#      Fri Jul 18 13:35:24 2014 +0200
# Node ID afa61241e2957de3858aba2eb16f8c1b65842484
# Parent  6368ecc92be2d8e851686d7fb02163c600b5b843
Added new root prefixes option.
Root prefixes are used to set feature include and lib paths.

diff -r 6368ecc92be2 -r afa61241e295 auto/feature
--- a/auto/feature	Fri Jul 18 13:35:24 2014 +0200
+++ b/auto/feature	Fri Jul 18 13:35:24 2014 +0200
@@ -14,6 +14,13 @@
 
 ngx_found=no
 
+if test -n "$NGX_ROOT_PREFIXES"; then
+   for ngx_temp in $NGX_ROOT_PREFIXES; do
+       ngx_feature_inc_path="$ngx_feature_inc_path -I ${ngx_temp}/include"
+       ngx_feature_lib_path="$ngx_feature_lib_path -L ${ngx_temp}/lib"
+   done
+fi
+
 if test -n "$ngx_feature_name"; then
     ngx_have_feature=`echo $ngx_feature_name \
                    | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ`
@@ -40,9 +47,11 @@
 
 
 ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS $ngx_feature_inc_path \
-          -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_TEST_LD_OPT $ngx_feature_libs"
+          $ngx_feature_lib_path -o $NGX_AUTOTEST $NGX_AUTOTEST.c \
+          $NGX_TEST_LD_OPT $ngx_feature_libs"
 
 ngx_feature_inc_path=
+ngx_feature_lib_path=
 
 eval "/bin/sh -c \"$ngx_test\" >> $NGX_AUTOCONF_ERR 2>&1"