Use double quotes for LDFLAGS in -DLLVM_BUILD_INSTRUMENTED_COVERAGE

Mimics the changes in r372209 to handle the change of quotes in
r372226. Probably isn't sufficient for windows, but unbreaks the cmake
flag at least.

llvm-svn: 372791

Author: bogner

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -867,7 +867,7 @@ endif()
 
 option(LLVM_BUILD_INSTRUMENTED_COVERAGE "Build LLVM and tools with Code Coverage instrumentation" Off)
 mark_as_advanced(LLVM_BUILD_INSTRUMENTED_COVERAGE)
-append_if(LLVM_BUILD_INSTRUMENTED_COVERAGE "-fprofile-instr-generate='${LLVM_PROFILE_FILE_PATTERN}' -fcoverage-mapping"
+append_if(LLVM_BUILD_INSTRUMENTED_COVERAGE "-fprofile-instr-generate=\"${LLVM_PROFILE_FILE_PATTERN}\" -fcoverage-mapping"
   CMAKE_CXX_FLAGS
   CMAKE_C_FLAGS
   CMAKE_EXE_LINKER_FLAGS