Try to fix Windows using gcc instead of g++ to link the package.

configure

@@ -80,9 +80,11 @@ build_dir=src/leveldb-mcpe/build
     "-DCMAKE_AR=${AR}" \
     "-DCMAKE_RANLIB=${RANLIB}" \
     -DCMAKE_BUILD_TYPE=Release \
-    -DLEVELDB_BUILD_TESTS:BOOL=OFF \
+    -DBUILD_SHARED_LIBS:bool=OFF \
+    -DCMAKE_POSITION_INDEPENDENT_CODE:bool=ON \
     -DCMAKE_CXX_STANDARD=17 \
     -DCMAKE_CXX_EXTENSIONS:BOOL=OFF \
+    -DLEVELDB_BUILD_TESTS:BOOL=OFF \
     -Wno-dev
 )
 

src/Makevars.win

@@ -1,3 +1,4 @@
+
 PKG_CFLAGS = $(C_VISIBILITY)
 PKG_CXXFLAGS = $(CXX_VISIBILITY)
 PKG_CPPFLAGS = -pthread -I./leveldb-mcpe/include -I./leveldb-mcpe/build/include
@@ -11,7 +12,7 @@ $(shell mkdir -p leveldb-mcpe/build)
 
 leveldb-mcpe/build/libleveldb.a: leveldb-mcpe/Makefile.mingw leveldb-mcpe/build/include/port/port_config.h
 	$(MAKE) --directory=leveldb-mcpe/build -f ../Makefile.mingw \
-	CXX="$(CXX)" CXXFLAGS="$(CXXFLAGS)" \
+	CXX="$(CXX)" CXXFLAGS="$(CXXFLAGS) $(CXXPICFLAGS)" \
 	AR="$(AR)" RANLIB="$(RANLIB)"
 
 leveldb-mcpe/build/include/port/port_config.h: leveldb-mcpe/port_config.h.mingw

src/dummy.cpp

@@ -0,0 +1,3 @@
+/* This file is a dummy to signal to R that we need to link using a C++
+ * compiler.
+ */