mingw64 rocksdb link issue

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### Expected behavior
I am using mingw64 on windows

### Actual behavior
I installed by "pacman -S rocksdb"
by somehow
g++ a.c -lrocksdb

C:\msys64\tmp\cc1MC5r2.o:a.c:(.text+0xc7): undefined reference to `rocksdb::DBOptions::IncreaseParallelism(int)'
C:\msys64\tmp\cc1MC5r2.o:a.c:(.text+0xde): undefined reference to `rocksdb::ColumnFamilyOptions::OptimizeLevelStyleCompaction(unsigned long long)'
C:\msys64\tmp\cc1MC5r2.o:a.c:(.text+0x103): undefined reference to `rocksdb::DB::Open(rocksdb::Options const&, std::__cxx11::basic_string, std::allocator > const&, rocksdb::DB**)'
C:\msys64\tmp\cc1MC5r2.o:a.c:(.text$_ZN7rocksdb7OptionsC1Ev[_ZN7rocksdb7OptionsC1Ev]+0x1a): undefined reference to `rocksdb::DBOptions::DBOptions()'
C:\msys64\tmp\cc1MC5r2.o:a.c:(.text$_ZN7rocksdb7OptionsC1Ev[_ZN7rocksdb7OptionsC1Ev]+0x2c): undefined reference to `rocksdb::ColumnFamilyOptions::ColumnFamilyOptions()'

### Steps to reproduce the behavior
here is a.c
a.c)
#include
#include

#include "rocksdb/db.h"
#include "rocksdb/slice.h"
#include "rocksdb/options.h"

using namespace rocksdb;

std::string kDBPath = "/tmp/rocksdb_simple_example";

int main() {
DB* db;
Options options;
// Optimize RocksDB. This is the easiest way to get RocksDB to perform well
options.IncreaseParallelism();
options.OptimizeLevelStyleCompaction();
// create the DB if it's not already present
options.create_if_missing = true;

// open DB
Status s = DB::Open(options, kDBPath, &db);
assert(s.ok());

return 0;
}