Cite URL for MPICH 3.2 bug fix on macOS

Author: Damian Rouson

prerequisites/build-functions/build_and_install.sh

@@ -21,7 +21,7 @@ build_and_install()
   if [[ "${package_to_build}" != "gcc" ]]; then
 
     if [[ "${package_to_build}" == "mpich" && "${version_to_build}" == "3.2"  && "${OSTYPE}" == "darwin"* ]]; then
-      info "Patching MPICH 3.2 on Mac OS due to segfault bug."
+      info "Patching MPICH 3.2 on Mac OS due to segfault bug (see http://lists.mpich.org/pipermail/discuss/2016-May/004764.html)."
       sed -i '' 's/} MPID_Request ATTRIBUTE((__aligned__(32)));/} ATTRIBUTE((__aligned__(32))) MPID_Request;/g' \
 	  "${download_path}/${package_source_directory}/src/include/mpiimpl.h"
     fi