In #127378 it was reported that builds without clspv targets enabled
were failing after #124727, as all targets had a dependency on a file
that only clspv targets generated.
A quick fix was merged in #127315 which wasn't correct. It moved the
dependency on those generated files to the spirv targets, instead of
onto the clspv targets. This means a build with spirv targets and
without clspv targets would see the same problems as #127378 reported.
I tried simply removing the requirement to explicitly add dependencies
to the custom command, relying instead on the file-level dependencies.
This didn't seem reliable enough; in some cases on a Makefiles build,
the clang command compiling (e.g.,) convert.cl would begin before the
file was fully written.
Instead, we keep the target-level dependency but automatically infer it
based on the generated file name, to avoid manual book-keeping of pairs
of files and targets.
This commit also fixes what looks like an unintended bug where, when
ENABLE_RUNTIME_SUBNORMAL was enabled, the OpenCL conversions weren't
being compiled.
15c2d1b328