build: quote possibly empty parameters

`CMAKE_SHARED_LIBRARY_PREFIX` is empty on Windows.  This accounts for
that and quotes the parameter which we otherwise will see as an error
due to insufficient parameters being passed.

Author: compnerd

lib/CMakeLists.txt

@@ -40,10 +40,10 @@ if (SWIFT_SWIFT_PARSER)
 
   # Determine the SwiftSyntax shared library files that were built as
   # part of earlyswiftsyntax.
-  list(TRANSFORM SWIFT_SYNTAX_MODULES PREPEND ${CMAKE_SHARED_LIBRARY_PREFIX}
+  list(TRANSFORM SWIFT_SYNTAX_MODULES PREPEND "${CMAKE_SHARED_LIBRARY_PREFIX}"
        OUTPUT_VARIABLE SWIFT_SYNTAX_SHARED_LIBRARIES)
   list(TRANSFORM SWIFT_SYNTAX_SHARED_LIBRARIES APPEND
-       ${CMAKE_SHARED_LIBRARY_SUFFIX}
+       "${CMAKE_SHARED_LIBRARY_SUFFIX}"
        OUTPUT_VARIABLE SWIFT_SYNTAX_SHARED_LIBRARIES)
 
   # Interface library to collect swiftinterfaces and swiftmodules from