[libc] Add path to include generated headers for hermetic tests

[jhuber6]

Summary

The generated header files live in the build directory's include path.
When targeting a hermetic build we want to make sure we only use headers
generated by the project itself if availible.

[jhuber6]

Fix

[jhuber6]

You need this include for all of them if we're building full standalone on the GPU. I'm not sure what a good way to express this is.

[sivachandra]

libc/test/UnitTest/CMakeLists.txt

30

Can we do:

if(LLVM_LIBC_FULL_BUILD)
  # If we are in full build mode, then we should use our own public headers.
  target_include_directories(${lib} PRIVATE ${LIBC_BUILD_DIR}/include)
endif()

We don't need the one on line 43?

[jhuber6]

Addressing comments

[jhuber6]

Update

[sivachandra]

libc/test/UnitTest/CMakeLists.txt

53

Nit: Move lines 56 and 57 above this if condition.

56

Remove these as they will be added outside of the if anyway.

libc/test/UnitTest/CMakeLists.txt

 add_library(
   LibcHermeticTest
   ${libc_test_srcs_common}
   HermeticTestUtils.cpp
 )
 
 foreach(lib LibcUnitTest LibcHermeticTest)
   target_include_directories(${lib} PUBLIC ${LIBC_SOURCE_DIR})
+  if(LLVM_LIBC_FULL_BUILD)
+    # If we are in full build mode, then we should use our own public headers.
+    target_include_directories(${lib} PRIVATE ${LIBC_BUILD_DIR}/include)
+  endif()
   target_compile_options(${lib} PRIVATE ${LIBC_HERMETIC_TEST_COMPILE_OPTIONS}
                          -fno-exceptions -fno-rtti)
   add_dependencies(${lib}
     libc.src.__support.c_string
     libc.src.__support.CPP.string
     libc.src.__support.CPP.string_view
     libc.src.__support.CPP.type_traits
     libc.src.__support.OSUtil.osutil
     libc.src.__support.uint128
   )
 endforeach()
 
 target_compile_options(LibcHermeticTest PRIVATE -ffreestanding -nostdlib -nostdlib++)
 
 add_library(
   LibcTestMain
   LibcTestMain.cpp
 )
 
 target_include_directories(LibcTestMain PUBLIC ${LIBC_SOURCE_DIR})
 target_compile_options(LibcTestMain PRIVATE -fno-exceptions -fno-rtti)
+if(LLVM_LIBC_FULL_BUILD)
+  target_include_directories(LibcTestMain PRIVATE ${LIBC_BUILD_DIR}/include)
+  target_compile_options(LibcTestMain PRIVATE ${LIBC_HERMETIC_TEST_COMPILE_OPTIONS})
+endif()
 add_dependencies(LibcTestMain LibcUnitTest)
 
 add_header_library(
   string_utils
   HDRS
   StringUtils.h
   DEPENDS
     libc.src.__support.CPP.string