chore: Install library to CMAKE_INSTALL_LIBDIR

Currently the library is installed in hardcoded /lib path. This patch
use the standard GNUInstallDirs macros to install it in either lib or
lib64, according to the user platform.

Signed-off-by: Robert-André Mauchin <zebob.m@gmail.com>

Author: Robert-André Mauchin

CMakeLists.txt

@@ -15,6 +15,7 @@ find_package(Threads REQUIRED)
 
 set (CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
 set (CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
+include("GNUInstallDirs")
 
 if (DISABLE_AUTO_INGEST)
   add_definitions(-DDISABLE_AUTO_INGEST)
@@ -130,4 +131,5 @@ if (NOT DISABLE_FTL_APP)
 endif()
 
 # Install rules
-install(TARGETS ftl DESTINATION lib)
+install(TARGETS ftl DESTINATION
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})