Windows debug flags were failing on Linux. These expressions can be t…

…ricky - make another try, but don't know if this works correctly on MSVC

llvm/CMakeLists.txt

@@ -42,7 +42,9 @@ if (ENABLE_LLVM)
     set(Z_BRL_PATCH_CMD "${PATCH_CMD};${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/llvm_z_brl.patch")
     set(PATCH_CMD "COMMAND")
   endif (TARGET ZLIB_BLD)
+  set(IS_MSVC 0)
   if (MSVC)
+    set(IS_MSVC 1)
     set(Z_NO_AST_INTRO_PATCH_CMD "${PATCH_CMD};${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/llvm_no_ast_introspection.patch")
     set(PATCH_CMD "COMMAND")
   endif (MSVC)
@@ -74,8 +76,8 @@ if (ENABLE_LLVM)
     -DCMAKE_INSTALL_LIBDIR:PATH=${LIB_DIR}
     -DCMAKE_INSTALL_RPATH=${CMAKE_BUNDLE_INSTALL_PREFIX}/${LIB_DIR}
     # we don't need LLVM itself to be debuggable.  Prevents .pdb and .ilk bloat.
-    -DCMAKE_CXX_FLAGS_DEBUG="$<$<CONFIG:Debug>:/DEBUG:NONE>"
-    -DCMAKE_EXE_LINKER_FLAGS_DEBUG="$<$<CONFIG:Debug>:/DEBUG:NONE /INCREMENTAL:NO>"
+    $<AND:${IS_MSVC},$<CONFIG:Debug>:-DCMAKE_CXX_FLAGS_DEBUG=/DEBUG:NONE>
+    $<AND:${IS_MSVC},$<CONFIG:Debug>:-DCMAKE_EXE_LINKER_FLAGS_DEBUG=/DEBUG:NONE /INCREMENTAL:NO>
     LOG_CONFIGURE ${EXT_BUILD_QUIET}
     LOG_BUILD ${EXT_BUILD_QUIET}
     LOG_INSTALL ${EXT_BUILD_QUIET}