cmake: fix typo in CXXFLAGS (was CXXLFAGS)

CMakeLists.txt

@@ -23,7 +23,7 @@ option(ENABLE_COMPRESSION "Enable gzip compression" ON)
 option(ENABLE_TESTING "Build tests" ON)
 option(USE_THIRDPARTY_LIBRARIES "Use 3rdParty submodules" ON)
 option(THIRDPARTY_CIVETWEB_WITH_SSL "Enable SSL support for embedded civetweb source code")
-option(OVERRIDE_CXX_STANDARD_FLAGS "Force building with -std=c++14 even if the CXXLFAGS are configured differently" ON)
+option(OVERRIDE_CXX_STANDARD_FLAGS "Force building with -std=c++14 even if the CXXFLAGS are configured differently" ON)
 option(GENERATE_PKGCONFIG "Generate and install pkg-config files" ${UNIX})
 option(RUN_IWYU "Run include-what-you-use" OFF)