When checking if the compiler supports compressed debug sections we need to
actually link instead of just compile.  Otherwise the compiler thinks that
they are supported, but gold does not support -gz=zlib.

Upstream-Status: Backport (r16459)
Signed-off-by: Ross Burton <ross.burton@intel.com>

--- a/configure.ac~	2017-07-11 11:53:16.000000000 +0100
+++ b/configure.ac	2017-07-11 18:16:13.674130483 +0100
@@ -2119,7 +2119,7 @@
 safe_CFLAGS=$CFLAGS
 CFLAGS="-g -gz=zlib"
 
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]], [[
+AC_LINK_IFELSE([AC_LANG_PROGRAM([[ ]], [[
   return 0;
 ]])], [
 ac_have_gz_zlib=yes
@@ -2139,7 +2139,7 @@
 safe_CFLAGS=$CFLAGS
 CFLAGS="-g -gz=zlib-gnu"
 
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]], [[
+AC_LINK_IFELSE([AC_LANG_PROGRAM([[ ]], [[
   return 0;
 ]])], [
 ac_have_gz_zlib_gnu=yes