tools/cmake: update to 3.20.3 + build with Ninja

Compile with Ninja. Ninja compiles faster and is more stable with
parallel builds. Routines copied from cmake.mk.

Speed improves from:

Executed in	127.47 secs	fish		external
usr time	17.02 mins	446.00 micros	17.02 mins
sys time	1.18 mins	40.00 micros	1.18 mins

to:

Executed in	118.91 secs	fish		external
usr time	17.28 mins	499.00 micros	17.28 mins
sys time	1.13 mins	45.00 micros	1.13 mins

Signed-off-by: Rosen Penev <rosenp@gmail.com>

tools/cmake/Makefile

@@ -7,14 +7,14 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=cmake
-PKG_VERSION:=3.19.1
+PKG_VERSION:=3.20.3
 PKG_RELEASE:=1
 PKG_CPE_ID:=cpe:/a:kitware:cmake
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://github.com/Kitware/CMake/releases/download/v$(PKG_VERSION)/ \
 		https://cmake.org/files/v3.19/
-PKG_HASH:=1d266ea3a76ef650cdcf16c782a317cb4a7aa461617ee941e389cb48738a3aba
+PKG_HASH:=4d008ac3461e271fcfac26a05936f77fc7ab64402156fb371d41284851a651b8
 
 HOST_BUILD_PARALLEL:=1
 HOST_CONFIGURE_PARALLEL:=1
@@ -29,7 +29,20 @@ HOST_CONFIGURE_VARS += \
 
 HOST_CONFIGURE_ARGS := \
 	$(if $(MAKE_JOBSERVER),--parallel="$(MAKE_JOBSERVER)") \
-	--prefix=$(STAGING_DIR_HOST)
+	--prefix="$(STAGING_DIR_HOST)" \
+	--generator=Ninja
+
+define Host/Compile/Default
+	+$(NINJA) -C $(HOST_BUILD_DIR) $(1)
+endef
+
+define Host/Install/Default
+	+$(NINJA) -C $(HOST_BUILD_DIR) install
+endef
+
+define Host/Uninstall/Default
+	+$(NINJA) -C $(HOST_BUILD_DIR) uninstall
+endef
 
 ifneq ($(findstring c,$(OPENWRT_VERBOSE)),)
   HOST_MAKE_FLAGS += VERBOSE=1