Build with boost threading=multi.

Author: evoskuil

install.sh

@@ -170,7 +170,7 @@ echo "  with_pkgconfigdir: $with_pkgconfigdir"
 # Define boost options for gcc.
 #------------------------------------------------------------------------------
 BOOST_OPTIONS_GCC=\
-"threading=single "\
+"threading=multi "\
 "variant=release "\
 "--disable-icu "\
 "--with-date_time "\
@@ -190,7 +190,7 @@ BOOST_OPTIONS_CLANG=\
 "toolset=clang "\
 "cxxflags=-stdlib=${boost_stdlib} "\
 "linkflags=-stdlib=${boost_stdlib} "\
-"threading=single "\
+"threading=multi "\
 "variant=release "\
 "--disable-icu "\
 "--with-date_time "\