cmake: General improvements to libusb linking

Delegates libusb external communication to externals/CMakeLists.txt
Ensures an interface library `usb` for every pathway
input_common just links to the `usb` library now
externals/libusb/CMakeLists.txt sets variables to override SDL2's libusb
finding
Other minor cleanup

CMakeLists.txt

@@ -422,18 +422,22 @@ elseif (TARGET Boost::boost)
 endif()
 
 # Ensure libusb is properly configured (based on dolphin libusb include)
-if(NOT APPLE)
+if(NOT APPLE AND NOT YUZU_USE_BUNDLED_LIBUSB)
     include(FindPkgConfig)
     if (PKG_CONFIG_FOUND)
         pkg_check_modules(LIBUSB QUIET libusb-1.0>=1.0.24)
     else()
         find_package(LibUSB)
     endif()
-endif()
-if (NOT LIBUSB_FOUND OR YUZU_USE_BUNDLED_LIBUSB)
-    add_subdirectory(externals/libusb)
-    set(LIBUSB_INCLUDE_DIR "${CMAKE_SOURCE_DIR}/externals/libusb/libusb/libusb")
-    set(LIBUSB_LIBRARIES usb)
+
+    if (NOT LIBUSB_FOUND)
+        message(WARNING "libusb not found, falling back to externals")
+        set(YUZU_USE_BUNDLED_LIBUSB ON)
+    else()
+        add_library(usb INTERFACE)
+        target_include_directories(usb INTERFACE "${LIBUSB_INCLUDE_DIRS}")
+        target_link_libraries(usb INTERFACE "${LIBUSB_LIBRARIES}")
+    endif()
 endif()
 
 # List of all FFmpeg components required

externals/CMakeLists.txt

@@ -45,6 +45,11 @@ target_include_directories(microprofile INTERFACE ./microprofile)
 add_library(unicorn-headers INTERFACE)
 target_include_directories(unicorn-headers INTERFACE ./unicorn/include)
 
+# libusb
+if (NOT LIBUSB_FOUND OR YUZU_USE_BUNDLED_LIBUSB)
+    add_subdirectory(libusb)
+endif()
+
 # SDL2
 if (NOT SDL2_FOUND AND ENABLE_SDL2)
     if (NOT WIN32)

externals/libusb/CMakeLists.txt

@@ -1,4 +1,7 @@
-if (MINGW OR NOT WIN32)
+set(LIBUSB_FOUND ON CACHE BOOL "libusb is present" FORCE)
+set(LIBUSB_VERSION "1.0.24" CACHE STRING "libusb version string" FORCE)
+
+if (MINGW OR (${CMAKE_SYSTEM_NAME} MATCHES "Linux"))
     # GNU toolchains for some reason doesn't work with the later half of this CMakeLists after
     # updating to 1.0.24, so we do it the old-fashioned way for now.
 
@@ -21,17 +24,19 @@ if (MINGW OR NOT WIN32)
     set(LIBUSB_MAKEFILE "${LIBUSB_PREFIX}/Makefile")
 
     if (MINGW)
-        set(LIBUSB_LIBRARY "${LIBUSB_PREFIX}/libusb/.libs/libusb-1.0.dll.a")
+        set(LIBUSB_LIBRARIES "${LIBUSB_PREFIX}/libusb/.libs/libusb-1.0.dll.a" CACHE PATH "libusb library path" FORCE)
         set(LIBUSB_SHARED_LIBRARY "${LIBUSB_PREFIX}/libusb/.libs/libusb-1.0.dll")
         set(LIBUSB_SHARED_LIBRARY_DEST "${CMAKE_BINARY_DIR}/bin/libusb-1.0.dll")
 
         set(LIBUSB_CONFIGURE_ARGS --host=x86_64-w64-mingw32 --build=x86_64-windows)
     else()
-        set(LIBUSB_LIBRARY "${LIBUSB_PREFIX}/libusb/.libs/libusb-1.0.so")
-        set(LIBUSB_SHARED_LIBRARY "${LIBUSB_LIBRARY}")
+        set(LIBUSB_LIBRARIES "${LIBUSB_PREFIX}/libusb/.libs/libusb-1.0.so" CACHE PATH "libusb library path" FORCE)
+        set(LIBUSB_SHARED_LIBRARY "${LIBUSB_LIBRARIES}")
         set(LIBUSB_SHARED_LIBRARY_DEST "${CMAKE_BINARY_DIR}/bin/libusb-1.0.so")
     endif()
 
+    set(LIBUSB_INCLUDE_DIRS "${LIBUSB_SRC_DIR}/libusb" CACHE PATH "libusb headers path" FORCE)
+
     # Causes "externals/libusb/libusb/libusb/os/windows_winusb.c:1427:2: error: conversion to non-scalar type requested", so cannot statically link it for now.
     # set(LIBUSB_CFLAGS "-DGUID_DEVINTERFACE_USB_DEVICE=\\(GUID\\){0xA5DCBF10,0x6530,0x11D2,{0x90,0x1F,0x00,0xC0,0x4F,0xB9,0x51,0xED}}")
 
@@ -39,7 +44,7 @@ if (MINGW OR NOT WIN32)
 
     add_custom_command(
         OUTPUT
-            "${LIBUSB_LIBRARY}"
+            "${LIBUSB_LIBRARIES}"
         COMMAND
             make
         WORKING_DIRECTORY
@@ -77,13 +82,14 @@ if (MINGW OR NOT WIN32)
 
     add_custom_target(usb-bootstrap DEPENDS "${LIBUSB_CONFIGURE}")
     add_custom_target(usb-configure DEPENDS "${LIBUSB_MAKEFILE}" usb-bootstrap)
-    add_custom_target(usb-build ALL DEPENDS "${LIBUSB_LIBRARY}" usb-configure)
+    add_custom_target(usb-build ALL DEPENDS "${LIBUSB_LIBRARIES}" usb-configure)
     # Workaround since static linking didn't work out -- We need to copy the DLL to the bin directory
     add_custom_target(usb-copy ALL DEPENDS "${LIBUSB_SHARED_LIBRARY_DEST}" usb-build)
 
     add_library(usb INTERFACE)
     add_dependencies(usb usb-copy)
-    target_link_libraries(usb INTERFACE "${LIBUSB_LIBRARY}")
+    target_link_libraries(usb INTERFACE "${LIBUSB_LIBRARIES}")
+    target_include_directories(usb INTERFACE "${LIBUSB_INCLUDE_DIRS}")
 
     if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
         find_package(Libudev QUIET)
@@ -92,7 +98,7 @@ if (MINGW OR NOT WIN32)
             target_include_directories(usb INTERFACE "${LIBUDEV_INCLUDE_DIR}")
         endif()
     endif()
-else() # MINGW OR NOT WIN32
+else() # MINGW OR (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
     # Ensure libusb compiles with UTF-8 encoding on MSVC
     if(MSVC)
         add_compile_options(/utf-8)
@@ -248,4 +254,4 @@ else() # MINGW OR NOT WIN32
 
 
     configure_file(config.h.in config.h)
-endif() # MINGW
+endif() # MINGW OR (${CMAKE_SYSTEM_NAME} MATCHES "Linux")

src/input_common/CMakeLists.txt

@@ -71,8 +71,7 @@ if (ENABLE_SDL2)
     target_compile_definitions(input_common PRIVATE HAVE_SDL2)
 endif()
 
-target_include_directories(input_common SYSTEM PRIVATE ${LIBUSB_INCLUDE_DIR})
-target_link_libraries(input_common PRIVATE ${LIBUSB_LIBRARIES})
+target_link_libraries(input_common PRIVATE usb)
 
 create_target_directory_groups(input_common)
 target_link_libraries(input_common PUBLIC core PRIVATE common Boost::boost)