Don't use /implib when linking LLVM executables

[amccarth]

Summary

No import library is actually generated when linking the executables. Note that there was already code to do this for cywin and mingw.

This is a step toward eliminating the apparent circular dependency: lldb.lib (the fake import library) depends on lldb.exe, which depends on lldb.lib (the actual import library for (lib)lldb.

[chandlerc]

Honestly, Reid would be a much better reviewer here. I don't know enough about the windows options.

[rnk]

Is this still needed, or are we leaving liblldb alone and moving on with life?

cmake/modules/HandleLLVMOptions.cmake

463

I'd add a comment here saying that if we ever want to support loadable plugins on Windows, we should leave these flags alone.

Right now we don't support loadable plugins on Windows at all, so taking out these flags is fine.

[amccarth]

The need for this is gone, so I'll drop this.

cmake/modules/HandleLLVMOptions.cmake

if (C_SUPPORTS_FNO_FUNCTION_SECTIONS)
       # Don't add -ffunction-section if it can be disabled with -fno-function-sections.
       # Doing so will break sanitizers.
       add_flag_if_supported("-ffunction-sections" FFUNCTION_SECTIONS)
     endif()
     add_flag_if_supported("-fdata-sections" FDATA_SECTIONS)
   endif()
 endif()
 
 if(CYGWIN OR MINGW)
   # Prune --out-implib from executables. It doesn't make sense even
   # with --export-all-symbols.
   string(REGEX REPLACE "-Wl,--out-implib,[^ ]+ " " "
     CMAKE_C_LINK_EXECUTABLE "${CMAKE_C_LINK_EXECUTABLE}")
   string(REGEX REPLACE "-Wl,--out-implib,[^ ]+ " " "
     CMAKE_CXX_LINK_EXECUTABLE "${CMAKE_CXX_LINK_EXECUTABLE}")
+else(MSVC)
+  # Prune /implib from executables.
+  string(REGEX REPLACE "/implib:[^ ]+ " " "
+    CMAKE_C_LINK_EXECUTABLE "${CMAKE_C_LINK_EXECUTABLE}")
+  string(REGEX REPLACE "/implib:[^ ]+ " " "
+    CMAKE_CXX_LINK_EXECUTABLE "${CMAKE_CXX_LINK_EXECUTABLE}")
 endif()
 
 if(MSVC)
   # Remove flags here, for exceptions and RTTI.
   # Each target property or source property should be responsible to control
   # them.
   # CL.EXE complains to override flags like "/GR /GR-".
   string(REGEX REPLACE "(^| ) */EH[-cs]+ *( |$)" "\\1 \\2" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")