[LLVM-C] Fix omission of INSTALL_WITH_TOOLCHAIN to llvm_add_library()

Due to a misstake with r365902 that tried to simplify the install with
toolchain logic LLVM-C.dll was no longer being installed.

Patch By: Jakob Bornecrantz

llvm-svn: 370271

Author: tstellar

llvm/tools/llvm-shlib/CMakeLists.txt

@@ -182,6 +182,6 @@ if(MSVC)
     VERBATIM )
 
   # Finally link the target.
-  add_llvm_library(LLVM-C SHARED ${SOURCES} DEPENDS intrinsics_gen)
+  add_llvm_library(LLVM-C SHARED INSTALL_WITH_TOOLCHAIN ${SOURCES} DEPENDS intrinsics_gen)
 
 endif()