The compilation of SEISAN on a Mac is basically the same as for Solaris/Linux, in COM/SEISAN.bash or COM/SEISAN.csh, set SEISARCH to 'macosx' (Intel-based=newer Macs) or 'macosxppc' (PowerPC based).
You may also need to change the line $(fc) seed.for to $(fc) -fno-range-check seed.for in LIB/Makefile
If you have gcc/gfortran 4+ installed and your Mac is Intel-based, you should now be able to compile. You also need X-windows, which should be preinstalled or on the installation disk for OSX 10.5 and higher (for earlier versions, they can be downloaded and installed).
New Mac computers are 64 bit, this URL is also showing how to tell if you Intel based is 32 bit: http://support.apple.com/kb/ht3696.
Additional hints on MacOSX 10
In order to compile and link Seisan off the source distribution, you need to have gcc/gfortran and Xcode installed.
We recommend you install the following:
brew package manager: Copy the following line in the Terminal and press Enter: /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew /install/master/install)"
gcc compilers: Upon successful installation of brew, execute "brew install gcc" from the terminal.
XCODE: Either install it from the Mac store under
https://itunes.apple.com/us/app/xcode/id4977998x5?ls=1&mt=12#or from the terminal when you are automatically asked for it.
X11 Quartz: Download the dmg-file, doubleclick and install:
The compilation procedure is the same as for Linux. However, for more details see INF/readme_macosx.txt.
The GUI Seisan Explorer have not been tested on Mac!