[PATCH] tools/qemu-xen: remove CFLAGS for qemu build

[Olaf Hering <olaf@aepfle.de>]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1330015545 -3600
# Node ID 5bdbdcb03d60a7b58f41306ef39cb988100efbe4
# Parent  56214b978466914c1b9f8adb1158a3217a823e42
tools/qemu-xen: remove CFLAGS for qemu build

Currently qemu-xen gets build with CFLAGS only if CFLAGS was already in
the environment during make invocation. If CFLAGS is in environment then
make will append all of the various flags specified in xen Makefiles,
which is then passed to qemu configure. If CFLAGS is not set, then
configure will use just "-O2 -g" because make does not export its own
CFLAGS variable.

To make qemu-xen build consistent this change removes CFLAGS from the
environment so that only the CFLAGS from qemu configure script will be
used. This matches what is done in kvm.rpm and qemu.rpm where for
example RPM_OPT_FLAGS is not passes as CFLAGS. Otherwise those packages
would not build as well.

Passing makes CFLAGS to configure will lead to build errors:
- xen Makefiles append -std=gnu99, this breaks qemu build due to a bug
  in header file:
fpu/softfloat-specialize.h:107: error: initializer element is not constant
- in 32bit builds, qemus configure script will append -mcpu=i486 in an
  odd way, which leads to unknown gcc cmdline options due to a missing
  space
- xen Makefiles will append -Wall which will expose all sorts of style
  issues in the qemu code
- in one case some of the asm() blocks will not compile with gcc 4.6 in
  openSuSE 12.1

Until upstream qemu has fixed all these issues use no extra CFLAGS to
configure qemu-xen.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 56214b978466 -r 5bdbdcb03d60 tools/Makefile
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -146,6 +146,7 @@ subdir-all-qemu-xen-dir subdir-install-q
 		source=.; \
 	fi; \
 	cd qemu-xen-dir; \
+	env -u CFLAGS \
 	$$source/configure --enable-xen --target-list=i386-softmmu \
 		--source-path=$$source \
 		--extra-cflags="-I$(XEN_ROOT)/tools/include \