With boost 1.88, two includes are explicitly needed for the NasalHash to compile. Still compiles with boost 1.84.
Index: Makefile =================================================================== RCS file: /cvs/ports/graphics/simgear/Makefile,v diff -u -p -r1.24 Makefile --- Makefile 30 Mar 2024 16:43:41 -0000 1.24 +++ Makefile 22 Apr 2025 18:45:10 -0000 @@ -1,6 +1,7 @@ COMMENT = library set for simulations, games and visualizations DISTNAME = simgear-2020.3.19 +REVISION = 0 SHARED_LIBS += SimGearCore 7.0 # 2.10 SHARED_LIBS += SimGearScene 7.0 # 2.10 Index: patches/patch-simgear_nasal_cppbind_NasalHash_hxx =================================================================== RCS file: patches/patch-simgear_nasal_cppbind_NasalHash_hxx diff -N patches/patch-simgear_nasal_cppbind_NasalHash_hxx --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ patches/patch-simgear_nasal_cppbind_NasalHash_hxx 22 Apr 2025 18:45:10 -0000 @@ -0,0 +1,12 @@ +Index: simgear/nasal/cppbind/NasalHash.hxx +--- simgear/nasal/cppbind/NasalHash.hxx.orig ++++ simgear/nasal/cppbind/NasalHash.hxx +@@ -24,6 +24,8 @@ + + #include <simgear/structure/map.hxx> + #include <boost/iterator/iterator_facade.hpp> ++#include <boost/mpl/if.hpp> ++#include <boost/type_traits/is_convertible.hpp> + + namespace nasal + {