Troubleshooting optipng install with brew install optipng - macos

Question

I've been having a go at this issue the whole evening on my mac terminal window. I'm having difficulty installing optipng with 'brew install optipng' on my mac.
Here is a log from terminal after 'brew install optipng'
==> Downloading https://downloads.sourceforge.net/project/optipng/OptiPNG/optipn
Already downloaded: /Library/Caches/Homebrew/optipng-0.7.5.tar.gz
==> ./configure --with-system-zlib --prefix=/usr/local/Cellar/optipng/0.7.5 --ma
==> make install
_main in optipng.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [optipng] Error 1
make: *** [install] Error 2
READ THIS: https://github.com/Homebrew/homebrew/wiki/troubleshooting
Naturally, I followed the link to github, and tried getting somewhere with brew doctor, instructions suggested by brew doctor, and even brew update.
I will include some of the warnings from brew doctor here, and will follow up with the whole log if need be (I don't want to clog up the post with unnecessary info).
Warning: gettext files detected at a system prefix
These files can cause compilation and link failures, especially if they
are compiled with improper architectures. Consider removing these files:
/usr/local/lib/libintl.dylib
Warning: Your XQuartz (2.7.4) is outdated
Please install XQuartz 2.7.5:
https://xquartz.macosforge.org
Warning: Python is installed at /Library/Frameworks/Python.framework
Warning: You have MacPorts or Fink installed:
/opt/local/bin/port
Warning: Unbrewed dylibs were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Warning: Unbrewed .la files were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Warning: Unbrewed static libraries were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Any help would greatly be appreciated.
Thanks

Answer 1

This one was really frustrating for me, but I managed to resolve the homebrew doctor issues, heres how:
Warning: Python is installed at /Library/Frameworks/Python.framework
I had multiple versions of Python installed, so I went ahead and deleted this one with:
sudo rm -rf /Library/Frameworks/Python.framework
Warning: You have MacPorts or Fink installed:
This one was a lot more difficult, my Macports had a PATH issues, so I had to add the path where it was located with terminal, then delete it from there.
Warning: Unbrewed dylibs were found in /usr/local/lib.
I deleted these with rm on terminal.
Warning: Unbrewed .la files were found in /usr/local/lib.
Deleted.
Unbrewed static libraries were found in /usr/local/lib.
If i'm not mistaken, I did brew prune here.
There was also changing the permissions in all my PATH files from root to me.
After doing this optipng installed fine.