Description:
Problem appear with cmake-3.13.1-1 in old version cmake-3.12.4-1 everything works fine.

If I use boost in a cmake project and use FindBoost.cmake provided by this cmake package
with
find_package(Boost REQUIRED COMPONENTS thread)

I get output in cmake with : MESSAGE(${Boost_LIBRARIES})

Outputstring:

/usr/lib/libboost_thread.so-lpthread/usr/lib/libboost_chrono.so/usr/lib/libboost_system.so/usr/lib/libboost_date_time.so/usr/lib/libboost_atomic.so

so there is a "-lpthread" inside the string of ${Boost_LIBRARIES}
wich leads to errors when cmake generates make files and and gcc try to link against -l-lpthread

I have this problem on 2 pcs even with plain new installed Archlinux just with newest boost package
boost 1.68.0-2
boost-libs 1.68.0-2

in old version cmake-3.12.4-1
the Outputstring of MESSAGE(${Boost_LIBRARIES}) is:
/usr/lib/libboost_date_time.so/usr/lib/libboost_system.so/usr/lib/libboost_thread.so/usr/lib/libboost_chrono.so/usr/lib/libboost_atomic.so

as expected

Steps to reproduce:
small cmake project with
find_package(Boost REQUIRED COMPONENTS thread)
MESSAGE(${Boost_LIBRARIES})