Installation.md

@@ -69,6 +69,29 @@ Successfully installed shakemap
 Type 'conda activate shakemap' to use this new virtual environment.
 ```
 
+On some OSs, you may see errors that end with something like:
+
+```
+ ...
+ error: command 'clang' failed with exit status 1
+ ----------------------------------------
+ERROR: Command errored out with exit status 1: /home/shake_hi/miniconda/envs/shakemap/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/home/shake_hi/shakemap_src/setup.py'"'"'; __file__='"'"'/home/shake_hi/shakemap_src/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' develop --no-deps Check the logs for full command output.
+Failed to pip install this package. Exiting.
+```
+If you see that error, edit setup.py and change the line:
+
+```
+os.environ['CC'] = 'clang'
+```
+
+to:
+
+```
+os.environ['CC'] = 'gcc'
+```
+
+Then rerun install.sh.
+
 If you didn't already have conda configured prior to running the install script, you may need to source the bash profile; on OSX:
 ```
 source ~/.bash_profile