make all non hardware_ libraries foo add C preprocessor definition LIB_FOO=1, and remove bespoke definitions which were all undocumented anyway (#374)

src/rp2_common/pico_stdio_usb/CMakeLists.txt

@@ -1,5 +1,5 @@
 if (TARGET tinyusb_device_unmarked)
-    add_library(pico_stdio_usb INTERFACE)
+    pico_add_impl_library(pico_stdio_usb)
 
     target_include_directories(pico_stdio_usb INTERFACE ${CMAKE_CURRENT_LIST_DIR}/include)
 
@@ -15,8 +15,4 @@ if (TARGET tinyusb_device_unmarked)
         pico_time
         pico_unique_id
     )
-
-    target_compile_definitions(pico_stdio_usb INTERFACE
-            PICO_STDIO_USB=1
-    )
 endif()

src/rp2_common/pico_stdio_usb/stdio_usb.c

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#if !defined(TINYUSB_HOST_LINKED) && !defined(TINYUSB_DEVICE_LINKED)
+#if !defined(LIB_TINYUSB_HOST) && !defined(LIB_TINYUSB_DEVICE)
 #include "tusb.h"
 
 #include "pico/time.h"

src/rp2_common/pico_stdio_usb/stdio_usb_descriptors.c

@@ -26,7 +26,7 @@
  * THE SOFTWARE.
  */
 
-#if !defined(TINYUSB_HOST_LINKED) && !defined(TINYUSB_DEVICE_LINKED)
+#if !defined(LIB_TINYUSB_HOST) && !defined(LIB_TINYUSB_DEVICE)
 
 #include "tusb.h"
 #include "pico/stdio_usb/reset_interface.h"