configure: Allow builds without any system or user emulation

The old code aborted configure when no emulation target was selected.
Even after removing the 'exit 1', it tried to read from STDIN
when QEMU was configured with

    configure' '--disable-user' '--disable-system'

This is fixed here.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

2 files changed, 5 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index def2ae23cd..04642975af 100644
--- a/Makefile
+++ b/Makefile
@@ -52,8 +52,13 @@ SUBDIR_MAKEFLAGS=$(if $(V),,--no-print-directory) BUILD_DIR=$(BUILD_DIR)
 SUBDIR_DEVICES_MAK=$(patsubst %, %/config-devices.mak, $(TARGET_DIRS))
 SUBDIR_DEVICES_MAK_DEP=$(patsubst %, %/config-devices.mak.d, $(TARGET_DIRS))
 
+ifeq ($(SUBDIR_DEVICES_MAK),)
+config-all-devices.mak:
+	$(call quiet-command,echo '# no devices' > $@,"  GEN   $@")
+else
 config-all-devices.mak: $(SUBDIR_DEVICES_MAK)
 	$(call quiet-command,cat $(SUBDIR_DEVICES_MAK) | grep =y | sort -u > $@,"  GEN   $@")
+endif
 
 -include $(SUBDIR_DEVICES_MAK_DEP)
 
diff --git a/configure b/configure
index 1b865174e1..8f99b7b941 100755
--- a/configure
+++ b/configure
@@ -1286,10 +1286,6 @@ if test -z "$target_list" ; then
 else
     target_list=`echo "$target_list" | sed -e 's/,/ /g'`
 fi
-if test -z "$target_list" ; then
-    echo "No targets enabled"
-    exit 1
-fi
 # see if system emulation was really requested
 case " $target_list " in
   *"-softmmu "*) softmmu=yes