Merge pull request #8924 from OTAkeys/pr/fix_spiffs_c11

pkg/spiffs: remove c11 dependency and clean-up makefile

pkg/spiffs/Makefile

 PKG_NAME=spiffs
 PKG_URL=https://github.com/pellepl/spiffs.git
 PKG_VERSION=287148c46587089c4543a21eef2d6e9e14b88364
-PKG_BUILDDIR ?= $(PKGDIRBASE)/$(PKG_NAME)
-
-CFLAGS += -std=c11
+PKG_LICENSE=MIT
 
 .PHONY: all
 
 all: git-download
-	@mkdir -p "$(PKG_BUILDDIR)/riotbuild"
-	@cp $(PKG_BUILDDIR)/src/*.c $(PKG_BUILDDIR)/src/*.h $(PKG_BUILDDIR)/riotbuild
-
-	@echo 'MODULE:=spiffs' > $(PKG_BUILDDIR)/riotbuild/Makefile
-	@echo 'include $$(RIOTBASE)/Makefile.base' >> $(PKG_BUILDDIR)/riotbuild/Makefile
-
-	"$(MAKE)" -C $(PKG_BUILDDIR)/riotbuild
+	"$(MAKE)" -C $(PKG_BUILDDIR)/src -f $(CURDIR)/Makefile.spiffs
 
 include $(RIOTBASE)/pkg/pkg.mk

pkg/spiffs/Makefile.include

 INCLUDES += -I$(RIOTPKG)/spiffs/include
-INCLUDES += -I$(PKGDIRBASE)/spiffs/riotbuild/
+INCLUDES += -I$(PKGDIRBASE)/spiffs/src/
 
 ifneq (,$(filter spiffs_fs,$(USEMODULE)))
   DIRS += $(RIOTBASE)/pkg/spiffs/fs

pkg/spiffs/Makefile.spiffs

+MODULE := spiffs
+
+# Disable 'ISO C99 doesn’t support unnamed structs/unions [-Werror=pedantic]'
+CFLAGS += -Wno-pedantic
+
+include $(RIOTBASE)/Makefile.base