Help! DLL make faild under windows mingw.

I am doing a DLL project, it is in the backend/utils/mb. But it can not be maked under windows mingw.
I require everyone to help me. Thank your very much.

The error infomations are as follows.

Info: resolving _CurrentMemoryContext by linking to __imp__CurrentMemoryContext (auto-import)
Info: resolving _SPI_processed by linking to __imp__SPI_processed (auto-import)
Info: resolving _SPI_tuptable by linking to __imp__SPI_tuptable (auto-import)
Info: resolving _default_statistics_target by linking to __imp__default_statistics_target (auto-import)
fu000001.o(.idata$3+0xc): undefined reference to `libpostgres_a_iname'
fu000002.o(.idata$3+0xc): undefined reference to `libpostgres_a_iname'
fu000003.o(.idata$3+0xc): undefined reference to `libpostgres_a_iname'
fu000004.o(.idata$3+0xc): undefined reference to `libpostgres_a_iname'
fu000005.o(.idata$3+0xc): undefined reference to `libpostgres_a_iname'
fu000006.o(.idata$3+0xc): more undefined references to `libpostgres_a_iname' follow
nmth000000.o(.idata$4+0x0): undefined reference to `_nm__CurrentMemoryContext'
nmth000111.o(.idata$4+0x0): undefined reference to `_nm__SPI_processed'
nmth000118.o(.idata$4+0x0): undefined reference to `_nm__SPI_tuptable'
nmth000127.o(.idata$4+0x0): undefined reference to `_nm__default_statistics_target'
d:\MinGW\bin\dllwrap.exe: d:\MinGW\bin\gcc exited with status 1
make: *** [libnsqlgeom.dll] Error 1

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