configure: parse --enable/--disable-strip automatically, flip default

Always include the STRIP variable in config-host.mak (it's only used
by the s390-ccw firmware build, and it adds a default if configure
omitted it), and use meson-buildoptions.sh to turn
--enable/--disable-strip into -Dstrip.

The default is now not to strip the binaries like for almost every other
package that has a configure script.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -307,7 +307,6 @@ debug="no"
 sanitizers="no"
 tsan="no"
 fortify_source="$default_feature"
-strip_opt="yes"
 mingw32="no"
 gcov="no"
 EXESUF=""
@@ -892,7 +891,6 @@ for opt do
       debug_tcg="yes"
       debug_mutex="yes"
       debug="yes"
-      strip_opt="no"
       fortify_source="no"
   ;;
   --enable-sanitizers) sanitizers="yes"
@@ -903,8 +901,6 @@ for opt do
   ;;
   --disable-tsan) tsan="no"
   ;;
-  --disable-strip) strip_opt="no"
-  ;;
   --disable-slirp) slirp="disabled"
   ;;
   --enable-slirp) slirp="enabled"
@@ -1367,7 +1363,6 @@ Advanced options (experts only):
   --enable-debug           enable common debug build options
   --enable-sanitizers      enable default sanitizers
   --enable-tsan            enable thread sanitizer
-  --disable-strip          disable stripping binaries
   --disable-werror         disable compilation abort on warning
   --disable-stack-protector disable compiler-provided stack protection
   --audio-drv-list=LIST    set audio drivers to try if -audiodev is not used
@@ -3315,9 +3310,6 @@ echo "GIT_SUBMODULES_ACTION=$git_submodules_action" >> $config_host_mak
 if test "$debug_tcg" = "yes" ; then
   echo "CONFIG_DEBUG_TCG=y" >> $config_host_mak
 fi
-if test "$strip_opt" = "yes" ; then
-  echo "STRIP=${strip}" >> $config_host_mak
-fi
 if test "$mingw32" = "yes" ; then
   echo "CONFIG_WIN32=y" >> $config_host_mak
   if test "$guest_agent_with_vss" = "yes" ; then
@@ -3595,6 +3587,7 @@ echo "GLIB_LIBS=$glib_libs" >> $config_host_mak
 echo "GLIB_VERSION=$(pkg-config --modversion glib-2.0)" >> $config_host_mak
 echo "QEMU_LDFLAGS=$QEMU_LDFLAGS" >> $config_host_mak
 echo "LD_I386_EMULATION=$ld_i386_emulation" >> $config_host_mak
+echo "STRIP=$strip" >> $config_host_mak
 echo "EXESUF=$EXESUF" >> $config_host_mak
 echo "LIBS_QGA=$libs_qga" >> $config_host_mak
 
@@ -3812,7 +3805,6 @@ if test "$skip_meson" = no; then
         -Doptimization=$(if test "$debug" = yes; then echo 0; else echo 2; fi) \
         -Ddebug=$(if test "$debug_info" = yes; then echo true; else echo false; fi) \
         -Dwerror=$(if test "$werror" = yes; then echo true; else echo false; fi) \
-        -Dstrip=$(if test "$strip_opt" = yes; then echo true; else echo false; fi) \
         -Db_pie=$(if test "$pie" = yes; then echo true; else echo false; fi) \
         -Db_coverage=$(if test "$gcov" = yes; then echo true; else echo false; fi) \
         -Db_lto=$lto -Dcfi=$cfi -Dtcg=$tcg -Dxen=$xen \