Detect strlcpy on the fly (musl libc)

Detect strlcpy on the fly, as was done in falcosecurity/libs#110.

Signed-off-by: Mark Stemm <mark.stemm@gmail.com>

cmake/modules/falcosecurity-libs.cmake

@@ -63,5 +63,15 @@ set(USE_BUNDLED_JSONCPP ON CACHE BOOL "")
 
 list(APPEND CMAKE_MODULE_PATH "${FALCOSECURITY_LIBS_SOURCE_DIR}/cmake/modules")
 
+include(CheckSymbolExists)
+check_symbol_exists(strlcpy "string.h" HAVE_STRLCPY)
+if(HAVE_STRLCPY)
+	message(STATUS "Existing strlcpy found, will *not* use local definition by setting -DHAVE_STRLCPY.")
+	add_definitions(-DHAVE_STRLCPY)
+else()
+	message(STATUS "No strlcpy found, will use local definition")
+endif()
+
 include(libscap)
 include(libsinsp)
+