build: Serialize builds in testshade (#2012)

When building with:

- OptiX enabled (OSL_USE_OPTIX)
- Code Coverage disabled (NOT CODECOV)
- a parallel build

various components of the clang toolchain are likely to crash
as the testshade and libtestshade builds run in parallel and
can overwrite each other's intermediate results.

This chain adds explicit dependencies to serialize these builds,
avoiding toolchain crashes at a minimal performance cost.

---

Signed-off-by: Jean-Francois Panisset <[email protected]>

Author: jfpanisset

src/testshade/CMakeLists.txt

@@ -82,6 +82,9 @@ target_include_directories (testshade BEFORE PRIVATE ${OpenImageIO_INCLUDES})
 target_link_libraries (testshade
                        PRIVATE
                            oslexec oslquery oslcomp)
+if (OSL_USE_OPTIX)
+    add_dependencies(testshade testshade_ptx)
+endif ()
 
 install (TARGETS testshade RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} )
 
@@ -98,6 +101,7 @@ osl_optix_target(testshade)
 if (NOT CODECOV)
     # The 'libtestshade' library
     add_library ( "libtestshade" ${testshade_srcs} )
+    add_dependencies(libtestshade testshade)
 
     set_target_properties (libtestshade
                            PROPERTIES