Bug 1636817

Description of problem:

In C++11 the shared_ptr -> bool conversion is explicit. In custom time zone code, make the cast explicit. Fixes compilation failure in C++11

Please see patch and either upstream as boost 1.53-(release+1) or include 1.54 in next el7 release:

https://www.boost.org/patches/1_54_0/002-date-time.patch

Version-Release number of selected component (if applicable):

boost-1.53.0-27

How reproducible:

very

Steps to Reproduce:

NOTE: building gnucash on el7 requires EPEL---but the bug is not from EPEL, it is in the base `boost` library.

1. download https://download.fedoraproject.org/pub/fedora/linux/development/rawhide/Everything/source/tree/Packages/g/gnucash-3.3-1.fc30.src.rpm
2. yum install epel-release
3. yum build-dep gnucash-3.3-1.fc30.src.rpm
4. yum install boost-devel libsoup-devel
5. rpmbuild -bb <attached gnucash.spec>
   #^^ the attached spec was modified slightly to build on el7

Actual results:

/usr/include/boost/date_time/local_time/custom_time_zone.hpp: In instantiation of ‘bool boost::local_time::custom_time_zone_base<CharT>::has_dst() const [with CharT = char]’:
/root/rpmbuild/BUILD/gnucash-3.3/libgnucash/engine/gnc-timezone.cpp:756:1:   required from here
/usr/include/boost/date_time/local_time/custom_time_zone.hpp:67:30: error: cannot convert ‘const boost::shared_ptr<boost::date_time::dst_day_calc_rule<boost::gregorian::date> >’ to ‘bool’ in return
       return (dst_calc_rules_); //if calc_rule is set the tz has dst



Expected results:

It should compile ;)