math/curv: fix build on GCC architectures

libcurv/geom/viewer/fbo.cc, libcurv/geom/viewer/mesh.cc, libcurv/geom/viewer/text.cc and libcurv/geom/viewer/vertexLayout.cc need to include sys/types.h to make uint type known. /wrkdirs/usr/ports/math/curv/work/curv-0.4-127-g3caf3068/libcurv/geom/viewer/fbo.cc:42:26: error: 'uint' does not name a type; did you mean 'int'?

PR: 241418
Approved by: linimon (mentor), yuri (maintainer)