cmake: add -DFTDID2xx and use FindFtd2xx.cmake

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/usb/CMakeLists.txt

@@ -1,7 +1,12 @@
 message (INFO " - Adding USB platforms")
 set (mraa_LIB_SRCS_NOAUTO ${mraa_LIB_SRCS_NOAUTO}
   ${PROJECT_SOURCE_DIR}/src/usb/usb.c
-  ${PROJECT_SOURCE_DIR}/src/usb/ftdi_ft4222.c
   PARENT_SCOPE
 )
+if (FTDID2XX)
+  set (mraa_LIB_SRCS_NOAUTO
+    ${PROJECT_SOURCE_DIR}/src/usb/ftdi_ft4222.c
+    PARENT_SCOPE
+  )
+endif ()
 

src/usb/usb.c

@@ -26,13 +26,16 @@
 #include <string.h>
 
 #include "mraa_internal.h"
+#ifdef FTDID2XX
 #include "usb/ftdi_ft4222.h"
+#endif
 
 
 mraa_platform_t
 mraa_usb_platform_extender(mraa_board_t* board)
 {
     mraa_platform_t platform_type = MRAA_UNKNOWN_PLATFORM;
+#ifdef FTDID2XX
     if (mraa_ftdi_ft4222_init() == MRAA_SUCCESS) {
         unsigned int versionChip, versionLib;
         if (mraa_ftdi_ft4222_get_version(&versionChip, &versionLib) == MRAA_SUCCESS) {
@@ -47,5 +50,6 @@ mraa_usb_platform_extender(mraa_board_t* board)
         default:
             syslog(LOG_ERR, "Unknown USB Platform Extender, currently not supported by MRAA");
     }
+#endif
     return platform_type;
 }