Update cmake to install

CMakeLists.txt

@@ -8,4 +8,19 @@ file(GLOB_RECURSE RADIOLIB_SOURCES
 
 add_library(RadioLib ${RADIOLIB_SOURCES})
 
-target_include_directories(RadioLib PUBLIC "src" "${CMAKE_CURRENT_BINARY_DIR}/include")
+target_include_directories(RadioLib
+    PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
+           $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+
+include(GNUInstallDirs)
+
+install(TARGETS RadioLib
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+)
+
+install(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/src/
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/RadioLib
+  FILES_MATCHING PATTERN "*.h"
+)
+