[runtimes][libc] Keep the libc target as "libc".

[sivachandra]

Summary

It currently renamed to "llvmlibc" under the runtimes/boostrap build.
This prevents us from making a full libc build.

[phosek]

LGTM

llvm/runtimes/CMakeLists.txt

if(compiler_rt_path)
   endif()
 endif()
 
 # Create a list with the names of all the runtime projects in all uppercase and
 # with dashes turned to underscores. This gives us the CMake variable `prefixes`
 # for all variables that will apply to runtimes.
 foreach(entry ${runtimes})
   get_filename_component(projName ${entry} NAME)
-  if(projName STREQUAL "libc")
-    # For now, we will use the name "llvmlibc" for the libc project as it is
-    # not a full libc yet. Also, if we leave it as is, the "lib" prefix gets
-    # stripped below and the targets endup having the name "c", "check-c" etc.
-    set(projName "llvmlibc")
-  endif()
   string(REPLACE "-" "_" canon_name ${projName})
   string(TOUPPER ${canon_name} canon_name)
   list(APPEND prefixes ${canon_name})
   if (${canon_name} STREQUAL "OPENMP")
     list(APPEND prefixes "LIBOMP" "LIBOMPTARGET")
   endif()
   # Many compiler-rt options start with SANITIZER_ and DARWIN_ rather than
   # COMPILER_RT_, so when compiler-rt is enabled, consider both.
   if(canon_name STREQUAL "COMPILER_RT")
     list(APPEND prefixes SANITIZER DARWIN)
   endif()
-  if(canon_name STREQUAL "LLVMLIBC")
+  if(canon_name STREQUAL "LIBC")
     list(APPEND prefixes "LLVM_LIBC")
     list(APPEND prefixes "LIBC_")
   endif()
 
   string(FIND ${projName} "lib" LIB_IDX)
-  if(LIB_IDX EQUAL 0)
+  if(LIB_IDX EQUAL 0 AND NOT projName STREQUAL "libc")
     string(SUBSTRING ${projName} 3 -1 projName)
   endif()
   list(APPEND runtime_names ${projName})
 endforeach()
 
 function(runtime_default_target)
   cmake_parse_arguments(ARG "" "" "DEPENDS;PREFIXES" ${ARGN})