Merge branch 'trivial-patches' of git://github.com/stefanha/qemu

* 'trivial-patches' of git://github.com/stefanha/qemu:
  versatilepb: Use symbolic indices for ARM PIC
  qdev: kill bogus comment
  qemu-barrier: Fix compiler version check for future gcc versions
  hw: Add missing 'static' attribute for QEMUMachine
  cleanup useless return sentence
  qemu-sockets: Fix compiler warning (regression for MinGW)
  vnc: Fix spelling (hellmen -> hellman) in comment
  slirp: Fix spelling in comment (enought -> enough, insure -> ensure)
  tcg/arm: Use tcg_out_mov_reg rather than inline equivalent code
  cpu: Add missing 'static' attribute to qemu_global_mutex
  configure: Support empty target list (--target-list=)
  hw: Fix return value check for bdrv_read, bdrv_write

configure

@@ -125,7 +125,8 @@ cc_i386=i386-pc-linux-gnu-gcc
 libs_qga=""
 debug_info="yes"
 
-target_list=""
+# Don't accept a target_list environment variable.
+unset target_list
 
 # Default value for a variable defining feature "foo".
 #  * foo="no"  feature will only be used if --enable-foo arg is given
@@ -1288,7 +1289,7 @@ if ! "$python" -c 'import sys; sys.exit(sys.version_info < (2,4) or sys.version_
   exit 1
 fi
 
-if test -z "$target_list" ; then
+if test -z "${target_list+xxx}" ; then
     target_list="$default_target_list"
 else
     target_list=`echo "$target_list" | sed -e 's/,/ /g'`