From a user:

am trying to install Pegasus on macOS 10.12 ("Sierra") following the Homebrew formulae posted in the documentation. Unfortunately, I encounter errrors that are somewhat mysterious to me. It looks like perhaps a problem occurs when building the documentation? Anyway, below is my output:

$ brew install pegasus htcondor
==> Installing pegasus from pegasus-isi/tools
==> Downloading http://download.pegasus.isi.edu/pegasus/4.6.1/pegasus-source-4.6.1.tar.gz
Already downloaded: /Users/wijay/Library/Caches/Homebrew/pegasus-4.6.1.tar.gz
==> ant clean dist-common doc-manpages
Last 15 lines from /Users/wijay/Library/Logs/Homebrew/pegasus/01.ant:
[exec] ^
[exec] compilation error: file http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl line 38 element include
[exec] xsl:include : unable to load http://docbook.sourceforge.net/release/xsl/current/manpages/lists.xsl
[exec] http://docbook.sourceforge.net/release/xsl/current/manpages/pi.xsl:1: parser error : Document is empty
[exec]
[exec] ^
[exec] compilation error: file http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl line 41 element include
[exec] xsl:include : unable to load http://docbook.sourceforge.net/release/xsl/current/manpages/pi.xsl
[exec] make: *** [pegasus-config.1] Error 5
[exec] make: *** [pegasus-configure-glite.1] Error 5

BUILD FAILED
/private/tmp/pegasus-20161006-10885-1tgwaf7/pegasus-source-4.6.1/build.xml:220: exec returned: 2