Description of problem:
EPEL7 currently ships an outdated version of weechat: 1.5

1.9.1 is available in fedora, but does not build in EPEL at the moment:
Processing files: weechat-1.9.1-1.el7.x86_64
error: File not found by glob: /builddir/build/BUILDROOT/weechat-1.9.1-1.el7.x86_64/usr/share/doc/weechat-1.9.1/weechat_*.html
Executing(%doc): /bin/sh -e /var/tmp/rpm-tmp.80MT8p

This seems to be because weechat itself installs its docs to /usr/share/doc/weechat instead of /usr/share/doc/weechat-<version>

The following part of the specfile should handle this, but it seems non-functional.

  %if %{?_pkgdocdir:1}0
  %global _doc %{name}
  %else
  %global _doc %{name}-%{version}
  %global _pkgdocdir %{_docdir}/%{_doc}
  %endif

_pkgdocdir is defined on EL7:
# rpm --eval "%{_pkgdocdir}"
%{_docdir}/%{name}-%{version}

The following patch seems to make it build fine on EL7 and rawhide:

diff --git a/weechat.spec b/weechat.spec
index 87bbbf9..10c0146 100644
--- a/weechat.spec
+++ b/weechat.spec
@@ -2,7 +2,11 @@
 %global __provides_exclude_from ^%{_libdir}/weechat/plugins/.*$
 
 %if %{?_pkgdocdir:1}0
+%if 0%{?rhel}
+%global _doc %{name}-%{version}
+%else
 %global _doc %{name}
+%endif
 %else
 %global _doc %{name}-%{version}
 %global _pkgdocdir %{_docdir}/%{_doc}