qemu/configure: fix CFLAGS handling for i386

configure will generate incorrect CFLAGS which will lead to compile errors due to unknown gcc options, IFF CFLAGS was already in the environment during configure invocation.

Add a space before the -march=i486 gcc option.

This patch is against the qemu-xen tree, but it should apply also to qemu.git since it has the same issue. Please apply to both trees.

Signed-off-by Olaf Hering <[email protected]>

---
 configure |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: qemu-xen-dir-remote/configure
===================================================================

configure +1 -1

@@ -2637,7 +2637,7 @@ int main(int argc, char **argv)
 }
 EOF
   if ! compile_prog "" "" ; then
-    CFLAGS+="-march=i486"
+    CFLAGS+=" -march=i486"
   fi
 fi
 

This is the only usage of += outside Makefile fragments, so I wonder if its use may have been by accident. Is it safe in a POSIX context? Or should we better use CFLAGS="$CFLAGS -march=486"?

Quoted 4 lines

This is the only usage of += outside Makefile fragments, so I wonder if its use may have been by accident. Is it safe in a POSIX context? Or should we better use CFLAGS="$CFLAGS -march=486"?

Now that I look at the shebang, configure is a sh script and += is most likely a bash feature. So your suggestion for the assignment is correct.

This is the only usage of += outside Makefile fragments, so I wonder if its use may have been by accident. Is it safe in a POSIX context? Or should we better use CFLAGS="$CFLAGS -march=486"?
For QEMU_CFLAGS we use the pattern QEMU_CFLAGS="-options $QEMU_CFLAGS" to allow overriding options.

Quoted 5 lines · Andreas Färber

This is the only usage of += outside Makefile fragments, so I wonder if its use may have been by accident. Is it safe in a POSIX context? Or should we better use CFLAGS="$CFLAGS -march=486"?
For QEMU_CFLAGS we use the pattern QEMU_CFLAGS="-options $QEMU_CFLAGS" to allow overriding options.

For that matter, should this be setting QEMU_CFLAGS instead of CFLAGS? I have to say I'm not entirely sure what the difference is...