[cmake] Install 'clang-cpp' symlink

[mgorny]

Summary

Install the 'clang-cpp' symlink used to spawn the preprocessor. The code handling this suffix is already included in Driver. FreeBSD is already creating such a symlink in ports, and a similar one was requested by Gentoo/FreeBSD team. The goal is to handle software that takes a C preprocessor via a variable but does not handle passing options correctly (i.e. 'clang -E' does not work).

Bug: https://bugs.gentoo.org/478810

[joerg]

LGTM, have been doing that in NetBSD for ages as well.

Side note, someone from Apple please make sure that xcode gets a similar link.

[mgorny]

Thanks for the review. Proceeding with the commit now.

[mgorny]

I'm going to close this manually since it seems that Phabricator commit processing is stuck somehow.

tools/driver/CMakeLists.txt

 # Support plugins.
 if(CLANG_PLUGIN_SUPPORT)
   export_executable_symbols(clang)
 endif()
 
 add_dependencies(clang clang-headers)
 
 if(NOT CLANG_LINKS_TO_CREATE)
-  set(CLANG_LINKS_TO_CREATE clang++ clang-cl)
+  set(CLANG_LINKS_TO_CREATE clang++ clang-cl clang-cpp)
 
   if (WIN32)
     list(APPEND CLANG_LINKS_TO_CREATE ../msbuild-bin/cl)
   endif()
 endif()
 
 foreach(link ${CLANG_LINKS_TO_CREATE})
   add_clang_symlink(${link} clang)