errors during compilation

[jayhesselberth]

I get errors during compilation with gcc < 6.0 (gcc >=6.0 and clang++ are fine).

C:/Rtools/mingw_32/bin/g++  -std=c++0x -I"c:/R/include" -DNDEBUG -I../inst/include   -I"c:/RLibrary/Rcpp/include" -I"c:/RLibrary/BH/include" -I"c:/RLibrary/dplyr/include" -I"d:/Comp
In file included from ../inst/include/valr.h:6:0,
                 from RcppExports.cpp:4:
../inst/include/IntervalTree.h: In constructor 'IntervalTree<T, K>::IntervalTree(IntervalTree<T, K>::intervalVector&, std::size_t, std::size_t, K, K, std::size_t)':
../inst/include/IntervalTree.h:148:37: error: use of 'this' in a constant expression
                 if (interval.stop < center) {
                                     ^
../inst/include/IntervalTree.h:148:30: error: parse error in template argument list
                 if (interval.stop < center) {
                              ^
make: *** [RcppExports.o] Error 1

Any ideas? Might be related to #16?