nir: add builtin builder

also move some of the GLSL builtins over we will need for implementing
some OpenCL builtins

v2: replace NIR_IMM_FP by nir_imm_floatN_t in ported code
    fix up changes caused by swizzle rework

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Signed-off-by: Karol Herbst <kherbst@redhat.com>

src/compiler/nir/meson.build

@@ -87,6 +87,8 @@ files_libnir = files(
   'nir.c',
   'nir.h',
   'nir_builder.h',
+  'nir_builtin_builder.c',
+  'nir_builtin_builder.h',
   'nir_clone.c',
   'nir_constant_expressions.h',
   'nir_control_flow.c',