cmake: Fix header detection with CheckUSBHID

Make use of check_include_files to be able to also include
stdint.h when checking for the headers. Fixes detection of
usbhid.h on OpenBSD.

/usr/include/usbhid.h:40:2: error: unknown type name 'uint32_t'
   40 |         uint32_t _usage_page;
      |         ^

CMakeLists.txt

@@ -46,6 +46,7 @@ endif()
 
 include(CheckLibraryExists)
 include(CheckIncludeFile)
+include(CheckIncludeFiles)
 include(CheckLanguage)
 include(CheckSymbolExists)
 include(CheckCSourceCompiles)

cmake/sdlchecks.cmake

@@ -1113,22 +1113,22 @@ macro(CheckUSBHID)
   cmake_push_check_state()
   check_library_exists(usbhid hid_init "" LIBUSBHID)
   if(LIBUSBHID)
-    check_include_file(usbhid.h HAVE_USBHID_H)
+    check_include_files("stdint.h;usbhid.h" HAVE_USBHID_H)
     if(HAVE_USBHID_H)
       set(USB_CFLAGS "-DHAVE_USBHID_H")
     endif()
 
-    check_include_file(libusbhid.h HAVE_LIBUSBHID_H)
+    check_include_files("stdint.h;libusbhid.h" HAVE_LIBUSBHID_H)
     if(HAVE_LIBUSBHID_H)
       string(APPEND USB_CFLAGS " -DHAVE_LIBUSBHID_H")
     endif()
     set(USB_LIBS ${USB_LIBS} usbhid)
   else()
-    check_include_file(usb.h HAVE_USB_H)
+    check_include_files("stdint.h;usb.h" HAVE_USB_H)
     if(HAVE_USB_H)
       set(USB_CFLAGS "-DHAVE_USB_H")
     endif()
-    check_include_file(libusb.h HAVE_LIBUSB_H)
+    check_include_files("stdint.h;libusb.h" HAVE_LIBUSB_H)
     if(HAVE_LIBUSB_H)
       string(APPEND USB_CFLAGS " -DHAVE_LIBUSB_H")
     endif()