This package appears to include a private copy of valgrind.h. In the latest relase of valgrind 3.10.0 a bug was fixed for ppc32 and support was added for aarch64 and ppc64le. Please either update the private copy of valgrind.h (memcheck.h, callgrind.h, etc) or (better) make your package BuildRequires: valgrind-devel and use the system installed headers.
glib is where the ppc32 problem was discovered originally, so its copy of valgrind.h has had this fixed first...
Do note that upstream fixed it differently than done in glib, so please do make sure to sync to get the proper magic instruction sequence recognized by the latest valgrind.