meson: remove dummy_cpp

meson has gotten pretty smart about tracking C and C++ dependencies
(internal and external), and using the right linker. This wasn't always
the case and we created empty c++ files to force the use of the c++
linker. We don't need that any more.

Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

meson.build

@@ -1309,14 +1309,6 @@ endif
 
 # TODO: gallium driver dirs
 
-# FIXME: this is a workaround for #2326
-prog_touch = find_program('touch')
-dummy_cpp = custom_target(
-  'dummy_cpp',
-  output : 'dummy.cpp',
-  command : [prog_touch, '@OUTPUT@'],
-)
-
 foreach a : pre_args
   add_project_arguments(a, language : ['c', 'cpp'])
 endforeach

src/compiler/meson.build

@@ -62,7 +62,7 @@ subdir('nir')
 # dependency with nir/meson.build.
 spirv2nir = executable(
   'spirv2nir',
-  [files('spirv/spirv2nir.c'), dummy_cpp],
+  files('spirv/spirv2nir.c'),
   dependencies : [dep_m, dep_thread, idep_nir],
   include_directories : [inc_common, inc_nir, include_directories('spirv')],
   link_with : libmesa_util,

src/intel/vulkan/meson.build

@@ -220,7 +220,7 @@ if with_tests
       'anv_@0@'.format(t),
       executable(
         t,
-        ['tests/@0@.c'.format(t), dummy_cpp, anv_entrypoints[0]],
+        ['tests/@0@.c'.format(t), anv_entrypoints[0]],
         link_with : libvulkan_intel_test,
         dependencies : [dep_libdrm, dep_thread, dep_m, dep_valgrind],
         include_directories : [

src/mesa/drivers/dri/meson.build

@@ -44,7 +44,7 @@ endif
 if dri_drivers != []
   libmesa_dri_drivers = shared_library(
     'mesa_dri_drivers',
-    dummy_cpp,  # see meson #2180
+    [],
     link_whole : dri_drivers,
     link_with : [
       libmegadriver_stub, libdricommon, libxmlconfig, libglapi, libmesa_util,