[libc] Include (v)s(n)printf in baremetal configs

[phosek]

Summary

These are commonly used on baremetal targets. We disable float
support and other features to reduce the binary size. This would
ideally eventually be handled using the proposed config mechanism:
https://discourse.llvm.org/t/rfc-systematic-way-to-introduce-and-use-libc-config-options/72943
but for now we use a CMake conditional.

[sivachandra]

I am working on cleaning this up using the proposal here: https://discourse.llvm.org/t/rfc-systematic-way-to-introduce-and-use-libc-config-options/72943. But this is OK as it is a few days away to get the implementation to the final shape.

libc/config/baremetal/arm/entrypoints.txt

set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.strtok
     libc.src.string.strtok_r
 
     # inttypes.h entrypoints
     libc.src.inttypes.imaxabs
     libc.src.inttypes.imaxdiv
     libc.src.inttypes.strtoimax
     libc.src.inttypes.strtoumax
- 
+    # stdio.h entrypoints
+    libc.src.stdio.sprintf
+    libc.src.stdio.snprintf
+    libc.src.stdio.vsprintf
+    libc.src.stdio.vsnprintf
+ 
     # stdlib.h entrypoints
     libc.src.stdlib.abs
     libc.src.stdlib.atoi
     libc.src.stdlib.atof
     libc.src.stdlib.atol
     libc.src.stdlib.atoll
     libc.src.stdlib.bsearch
     libc.src.stdlib.div

libc/config/baremetal/arm/headers.txt

 set(TARGET_PUBLIC_HEADERS
     libc.include.ctype
     libc.include.fenv
     libc.include.errno
     libc.include.inttypes
     libc.include.math
+    libc.include.stdio
     libc.include.stdlib
     libc.include.string
     libc.include.strings
 )

libc/config/baremetal/riscv32/entrypoints.txt

set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.strtok_r
 
     # inttypes.h entrypoints
     libc.src.inttypes.imaxabs
     libc.src.inttypes.imaxdiv
     libc.src.inttypes.strtoimax
     libc.src.inttypes.strtoumax
 
+    # stdio.h entrypoints
+    libc.src.stdio.sprintf
+    libc.src.stdio.snprintf
+    libc.src.stdio.vsprintf
+    libc.src.stdio.vsnprintf
+
     # stdlib.h entrypoints
     libc.src.stdlib.abs
     libc.src.stdlib.atoi
     libc.src.stdlib.atol
     libc.src.stdlib.atoll
     libc.src.stdlib.bsearch
     libc.src.stdlib.div
     libc.src.stdlib.labs

libc/config/baremetal/riscv32/headers.txt

 set(TARGET_PUBLIC_HEADERS
     libc.include.ctype
     libc.include.fenv
     libc.include.errno
     libc.include.inttypes
     libc.include.math
+    libc.include.stdio
     libc.include.stdlib
     libc.include.string
     libc.include.strings
 )

libc/src/stdio/CMakeLists.txt

 if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
 endif()
 
 if(NOT LIBC_TARGET_ARCHITECTURE_IS_GPU)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/generic)
 endif()
 
+if(${LIBC_TARGET_OS} STREQUAL "baremetal")
+  list(APPEND printf_copts
+      "-DLIBC_COPT_PRINTF_DISABLE_FLOAT"
+      "-DLIBC_COPT_PRINTF_DISABLE_INDEX_MODE"
+      "-DLIBC_COPT_PRINTF_DISABLE_WRITE_INT"
+    )
+endif()
+
 add_subdirectory(printf_core)
 add_subdirectory(scanf_core)
 
 add_entrypoint_object(
   clearerr
   SRCS
     clearerr.cpp
   HDRS
DEPENDS
     libc.src.stdio.printf_core.writer
 )
 
 list(APPEND printf_deps
       libc.src.__support.arg_list
       libc.src.stdio.printf_core.vfprintf_internal
 )
 if(LLVM_LIBC_FULL_BUILD)
   list(APPEND printf_deps
       libc.src.__support.File.file
       libc.src.__support.File.platform_file
       libc.src.__support.File.platform_stdout
   )
 else()
- set(printf_copts "-DLIBC_COPT_PRINTF_USE_SYSTEM_FILE")
+  list(APPEND printf_copts "-DLIBC_COPT_PRINTF_USE_SYSTEM_FILE")
 endif()
 
 add_entrypoint_object(
   printf
   SRCS
     printf.cpp
   HDRS
     printf.h

libc/src/stdio/printf_core/CMakeLists.txt

DEPENDS
     libc.src.__support.common
     libc.src.__support.libc_assert
     libc.src.__support.uint
     libc.src.__support.uint128
     libc.src.__support.integer_to_string
     libc.src.__support.float_to_string
   COMPILE_OPTIONS
     -DLIBC_COPT_FLOAT_TO_STR_USE_MEGA_LONG_DOUBLE_TABLE
+    ${printf_copts}
 )
 
 
 add_object_library(
   printf_main
   SRCS
     printf_main.cpp
   HDRS