gdb/testsuite/
* gdb.cp/pr10728-x.cc: Return by value instead of pointer to coax
Clang into emitting the definition of the type.
* gdb.cp/pr10728-x.h: Ditto.
* gdb.cp/pr10728-y.cc: Ditto.
* valarith.c (value_ptrdiff): Added a test for a zero type length,
warn if found, and assume length = 1.
* gdb.cp/pr10728-x.h: New file.
* gdb.cp/pr10728-x.cc: New file.
* gdb.cp/pr10728-y.cc: New file.
* gdb.cp/pr10728.exp: New file.
* gdb.cp/Makefile.in (EXECUTABLES): Add pr10728