Use $(MAKE) for recursive make

On BSDs "make" is typically BSD make, while "gmake" is GNU make.

Signed-off-by: Ed Maste <emaste@freebsd.org>
Message-Id: <1427911118-21905-1-git-send-email-emaste@freebsd.org>
[Fix $(INSTALLER) too as reported by Fam Zheng. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Makefile

@@ -331,8 +331,8 @@ distclean: clean
 	rm -rf $$d || exit 1 ; \
         done
 	rm -Rf .sdk
-	if test -f pixman/config.log; then make -C pixman distclean; fi
-	if test -f dtc/version_gen.h; then make $(DTC_MAKE_ARGS) clean; fi
+	if test -f pixman/config.log; then $(MAKE) -C pixman distclean; fi
+	if test -f dtc/version_gen.h; then $(MAKE) $(DTC_MAKE_ARGS) clean; fi
 
 KEYMAPS=da     en-gb  et  fr     fr-ch  is  lt  modifiers  no  pt-br  sv \
 ar      de     en-us  fi  fr-be  hr     it  lv  nl         pl  ru     th \
@@ -532,7 +532,7 @@ installer: $(INSTALLER)
 INSTDIR=/tmp/qemu-nsis
 
 $(INSTALLER): $(SRC_PATH)/qemu.nsi
-	make install prefix=${INSTDIR}
+	$(MAKE) install prefix=${INSTDIR}
 ifdef SIGNCODE
 	(cd ${INSTDIR}; \
          for i in *.exe; do \