Fix syntax error
The include_files argument was malformed due to a missing `${` at the beginning.  Was expanding to (e.g.) the literal `Zstd_INCLUDE_DIRS}` instead of to the contents of the `Zstd_INCLUDE_DIRS` variable.
@@ -1085,7 +1085,7 @@ string(TOUPPER "${filter}" upfilter)
string(TOLOWER "${filter}" downfilter)
# Define a test flag for filter
IF(${filter}_FOUND)
- INCLUDE_DIRECTORIES(${filter}_INCLUDE_DIRS})
+ INCLUDE_DIRECTORIES(${${filter}_INCLUDE_DIRS})
SET(ENABLE_${upfilter} TRUE)
SET(HAVE_${upfilter} ON)
SET(STD_FILTERS "${STD_FILTERS} ${downfilter}")
