OpenMP Error Compiling FLOWExaFM

[Ubilot3000]

I downloaded MinGW and CMake to compile FLOWExaFM, but it can't seem to find a OpenMP C++ compiler . I don't know how to set the flag so it uses it. I'm running it through Git Bash on Windows to use the sh build.sh command. I'm unfamiliar with Julia and C so I don't know what I'm missing. Here's the error log:

$ sh build.sh --fopenmp
Removing existing build
Copying files
Configuring build
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... no
checking whether make supports nested variables... no
checking whether to enable maintainer-specific portions of Makefiles... no
checking for CC... no
checking for icpc... no
checking for g++... g++
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 we are using the GNU C++ compiler... yes
checking whether g++ accepts -g... yes
checking for style of include used by make... none
checking dependency style of g++... none
checking for ftn... no
checking for ifort... no
checking for gfortran... gfortran
checking whether we are using the GNU Fortran compiler... yes
checking whether gfortran accepts -g... yes
checking for ranlib... ranlib
checking for gcc... gcc
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking whether gcc understands -c and -o together... yes
checking dependency style of gcc... none
checking for ar... ar
checking the archiver (ar) interface... ar
checking for OpenMP flag of C++ compiler... unknown
configure: error: don't know how to enable OpenMP for C++
Compiling 3d
build.sh: line 46: make: command not found
cp: cannot stat 'build/3d/fmm': No such file or directory

Done!

Compile Summary:
julia version 1.10.5
CxxWrap v0.15.0 Info Packages marked with ⌃ have new versions available and may be upgradable. nothing

My problem is where it says it doesn't know how to enable OpenMP for C++.