configure: enable elf2dmp build for Windows hosts

After this patch contrib/elf2dmp can be built for Windows x86 and x86_64
hosts by mingw.
Signed-off-by: NViktor Prutyanov <viktor.prutyanov@phystech.edu>
Message-Id: <20181220012441.13694-7-viktor.prutyanov@phystech.edu>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Makefile

@@ -570,8 +570,8 @@ ifneq ($(EXESUF),)
 qemu-ga: qemu-ga$(EXESUF) $(QGA_VSS_PROVIDER) $(QEMU_GA_MSI)
 endif
 
-elf2dmp: LIBS = $(CURL_LIBS)
-elf2dmp: $(elf2dmp-obj-y)
+elf2dmp$(EXESUF): LIBS += $(CURL_LIBS)
+elf2dmp$(EXESUF): $(elf2dmp-obj-y)
 	$(call LINK, $^)
 
 ifdef CONFIG_IVSHMEM

configure

@@ -5790,8 +5790,8 @@ if test "$want_tools" = "yes" ; then
   if [ "$ivshmem" = "yes" ]; then
     tools="ivshmem-client\$(EXESUF) ivshmem-server\$(EXESUF) $tools"
   fi
-  if [ "$posix" = "yes" ] && [ "$curl" = "yes" ]; then
-    tools="elf2dmp $tools"
+  if [ "$curl" = "yes" ]; then
+      tools="elf2dmp\$(EXESUF) $tools"
   fi
 fi
 if test "$softmmu" = yes ; then