Building gmsh 4.7.0 from source

Hello,

I'm attempting to build gmsh 4.7.0 from source using CMake as I require some features that are only currently available in gmsh 4.7.0. Specifically, I'd like to use mesh size functions from pygmsh.

However, when I go to build gmsh from commit 0e1e5c of master, the linking stage fails stating:

[ 92%] Linking CXX shared library libgmsh.dylib
ld: library not found for -lpng
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [libgmsh.4.7.0.dylib] Error 1
make[1]: *** [CMakeFiles/shared.dir/all] Error 2
make: *** [all] Error 2

I followed the instructions with regard to typical CMake operations. libpng is installed on my MacOS (Catalina) and linked on my system. brew reports this in regard to libpng

Warning: libpng 1.6.37 is already installed and up-to-date
To reinstall 1.6.37, run `brew reinstall libpng`

I tried reinstalling libpng and received the same error as above with regard to linking when building gmsh from source.

Thank you for any help you can provide!