[libc] Remove old RPC host call extension for GPU (#120800)

Summary:
This was originally a hacked together function that served to just
implement some features for OpenMP. That has been moved into OpenMP
itself now that we have exported RPC properly. This can now be deleted.

Author: jhuber6

libc/config/gpu/entrypoints.txt

@@ -271,9 +271,6 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.locale.newlocale
     libc.src.locale.setlocale
     libc.src.locale.uselocale
-
-    # gpu/rpc.h entrypoints
-    libc.src.gpu.rpc_host_call
 )
 
 set(TARGET_LIBM_ENTRYPOINTS

libc/config/gpu/headers.txt

@@ -18,7 +18,4 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.uchar
     libc.include.features
     libc.include.locale
-
-    # Header for RPC extensions
-    libc.include.gpu_rpc
 )

libc/hdrgen/yaml/gpu/rpc.yaml

@@ -750,19 +750,6 @@ add_header_macro(
     .llvm-libc-types.struct_lconv
 )
 
-if(LIBC_TARGET_OS_IS_GPU)
-  file(MAKE_DIRECTORY ${LIBC_INCLUDE_DIR}/gpu)
-
-  add_header_macro(
-    gpu_rpc
-    ../libc/hdrgen/yaml/gpu/rpc.yaml
-    gpu/rpc.h.def
-    gpu/rpc.h
-    DEPENDS
-      .llvm_libc_common_h
-  )
-endif()
-
 if(NOT LLVM_LIBC_FULL_BUILD)
   # We don't install headers in non-fullbuild mode.
   return()

libc/include/CMakeLists.txt

@@ -9,6 +9,5 @@ add_object_library(
   HDRS
     rpc_client.h
   DEPENDS
-    libc.include.gpu_rpc
     libc.src.__support.GPU.utils
 )