build-pkg: build nonet and check-reqs early, ignore .waf* artefacts

Makefile

@@ -674,6 +674,9 @@ $(NONET_LIB): $(TOP_DIR)/tools/nonetwork.c | $(PREFIX)/$(BUILD)/lib/.gitkeep
 	@$(PRINTF_FMT) '[nonet lib]' '$@'
 	+@$(BUILD_CC) -shared -fPIC $(NONET_CFLAGS) -o $@ $<
 
+.PHONY: nonet-lib
+nonet-lib: $(NONET_LIB)
+
 .PHONY: shell
 shell: $(NONET_LIB)
 	$(PRELOAD) $(SHELL)

tools/build-pkg.lua

@@ -439,6 +439,7 @@ end
 local function gitInit()
     os.execute('mkdir -p ./usr')
     os.execute(GIT .. 'init --quiet')
+    os.execute('echo .waf* >> ./usr/.git/info/exclude')
 end
 
 local function gitTag(name)
@@ -1096,7 +1097,7 @@ local function main()
             MXE_DIR, MXE_DIR_EXPECTED)
     end
     gitInit()
-    assert(execute(("%s check-requirements MXE_TARGETS=%q"):format(
+    assert(execute(("%s check-requirements nonet-lib print-git-oneline MXE_TARGETS=%q"):format(
         tool 'make', table.concat(TARGETS, ' '))))
     if not max_items then
         downloadPackages()