How do I build liquid-dsp in Windows 10 using msys64

[PaulSHoff]

I inherited a msys64 project running on Windows 10. Told that our USRP only has Windows drivers so they were building gnuradio on msys64 using MINGW64 on Windows. CubicSDR seems to have a solution:
https://github.com/cjcliffe/CubicSDR/blob/master/external/liquid-dsp/How_to_build_liquid_dsp_for_Windows.txt
But this suggests it is old version.
https://sourceforge.net/p/mingw-w64/support-requests/141/

Since CutbicSDR refers to mingw32, I looked at C:\msys64\mingw32\ folder; the five folders are there (i.e., bin, etc, include, lib, and share) but are empty. Maybe the below error is related to this point?

What I did: clone liquid-dsp v1.4.0; downloaded the v1.5.0 tar.gz file and copied it on top of v1.4.0.
As a test, I had no issues building liquid-dsp v1.5.0 in VirtualBox having Ubuntu guest.
I see that config.h and makefile are dynamically created by ./configure. For this reason, the CutbicSDR instructions about copying config.h and makefile confuse me since they are not up to date with v1.5.0.

Copy config.h, makefile.mingw32, makefile.mingw64 in the liquid-dsp root directory.

In Windows 10 msys64 folder, ran ./bootstrap.sh and ./configure.

$ ./configure
configure: loading site script /etc/config.site
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.exe
checking for suffix of executables... .exe
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether the compiler supports GNU C... yes
checking whether gcc accepts -g... yes
checking for gcc option to enable C11 features... none needed
checking for a sed that does not truncate output... /usr/bin/sed
checking for grep that handles long lines and -e... /usr/bin/grep
checking for a BSD-compatible install... /usr/bin/install -c
checking for ranlib... ranlib
checking for error_at_line... no
checking build system type... x86_64-w64-mingw32
checking host system type... x86_64-w64-mingw32
checking for GNU libc compatible malloc... yes
checking for GNU libc compatible realloc... yes
checking for main in -lc... no
configure: error: Could not use standard C library

I tried defining LD_LIBRARY_PATH:

$ env | grep LIBRARY
LD_LIBRARY_PATH=/mingw64/lib
$ ls $LD_LIBRARY_PATH/libstd*
/mingw64/lib/libstdc++.a /mingw64/lib/libstdc++.dll.a /mingw64/lib/libstdc++.dll.a-gdb.py /mingw64/lib/libstdc++fs.a

The following works:

$ gcc -c hello.c
$ gcc hello.o -o Hello
$ ./Hello
Hello World

(and .\Hello works from a Windows 10 cmd window.)