[libvirt] [PATCH] Fix build for older gcc

[Jim Fehlig]

With gcc 4.3.4 I'm seeing the following warning failure

cc1: warnings being treated as errors
cc1: error: -funit-at-a-time is required for inlining of functions
that are only called once [-Wdisabled-optimization]

Add -funit-at-a-time to WARN_CFLAGS.
---
 m4/virt-compile-warnings.m4 |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4
index 819da8f..8df6f9c 100644
--- a/m4/virt-compile-warnings.m4
+++ b/m4/virt-compile-warnings.m4
@@ -112,6 +112,7 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
         gl_WARN_ADD([-fexceptions])
         gl_WARN_ADD([-fasynchronous-unwind-tables])
         gl_WARN_ADD([-fdiagnostics-show-option])
+        gl_WARN_ADD([-funit-at-a-time])
 
         if test "$enable_compile_warnings" = "error"
         then
-- 
1.7.3.1