Remove legacy CMake targets for libcxx and libcxxabi

We've been meaning to remove those targets for a while, and the fix is
simple enough cause they're all just aliases to other targets.

There's no doubt this commit will break some CI systems, however the
fix is trivial.

Differential Revision: https://reviews.llvm.org/D76104

libcxx/docs/BuildingLibcxx.rst

@@ -68,7 +68,7 @@ rebuilding LLVM as often. An out-of-tree build would look like this:
           -DLIBCXX_CXX_ABI_INCLUDE_PATHS=path/to/separate/libcxxabi/include \
           path/to/llvm-project/libcxx
   $ make
-  $ make check-libcxx # optional
+  $ make check-cxx # optional
 
 
 Experimental Support for Windows

libcxx/docs/TestingLibcxx.rst

@@ -8,9 +8,9 @@ Testing libc++
 Getting Started
 ===============
 
-libc++ uses LIT to configure and run its tests. 
+libc++ uses LIT to configure and run its tests.
 
-The primary way to run the libc++ tests is by using `make check-libcxx`. 
+The primary way to run the libc++ tests is by using `make check-cxx`.
 
 However since libc++ can be used in any number of possible
 configurations it is important to customize the way LIT builds and runs

libcxx/include/CMakeLists.txt

@@ -270,8 +270,5 @@ if (LIBCXX_INSTALL_HEADERS)
                               -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
     # Stripping is a no-op for headers
     add_custom_target(install-${CXX_HEADER_TARGET}-stripped DEPENDS install-${CXX_HEADER_TARGET})
-
-    add_custom_target(install-libcxx-headers DEPENDS install-${CXX_HEADER_TARGET})
-    add_custom_target(install-libcxx-headers-stripped DEPENDS install-${CXX_HEADER_TARGET}-stripped)
   endif()
 endif()

libcxx/src/CMakeLists.txt

@@ -392,5 +392,4 @@ if (NOT CMAKE_CONFIGURATION_TYPES AND (LIBCXX_INSTALL_LIBRARY OR
                       -DCMAKE_INSTALL_COMPONENT=cxx
                       -DCMAKE_INSTALL_DO_STRIP=1
                       -P "${LIBCXX_BINARY_DIR}/cmake_install.cmake")
-    add_custom_target(install-libcxx DEPENDS install-cxx)
 endif()

libcxx/test/CMakeLists.txt

@@ -83,8 +83,6 @@ if (LIBCXX_INCLUDE_TESTS)
     "Running libcxx tests"
     ${CMAKE_CURRENT_BINARY_DIR}
     DEPENDS cxx ${LIBCXX_TEST_DEPS})
-
-  add_custom_target(check-libcxx DEPENDS check-cxx)
 endif()
 
 if (LIBCXX_GENERATE_COVERAGE)

libcxxabi/src/CMakeLists.txt

@@ -295,7 +295,4 @@ if (NOT CMAKE_CONFIGURATION_TYPES AND LIBCXXABI_INSTALL_LIBRARY)
             -DCMAKE_INSTALL_COMPONENT=cxxabi
             -DCMAKE_INSTALL_DO_STRIP=1
             -P "${LIBCXXABI_BINARY_DIR}/cmake_install.cmake")
-
-  # TODO: This is a legacy target name and should be removed at some point.
-  add_custom_target(install-libcxxabi DEPENDS install-cxxabi)
 endif()

libcxxabi/test/CMakeLists.txt

@@ -81,6 +81,3 @@ add_lit_testsuite(check-cxxabi "Running libcxxabi tests"
   ${CMAKE_CURRENT_BINARY_DIR}
   DEPENDS ${LIBCXXABI_TEST_DEPS}
   )
-
-# TODO: This is a legacy target name and should be removed at some point.
-add_custom_target(check-libcxxabi DEPENDS check-cxxabi)