hidapi: add libiconv handling

hidapi uses iconv functions, which on uClibc without locale support is
provided by the external libiconv library. This commit adds the
necessary libiconv handling to make the hidapi package build on
!locale toolchains.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/hidapi/Config.in

@@ -4,6 +4,7 @@ config BR2_PACKAGE_HIDAPI
 	depends on BR2_TOOLCHAIN_HAS_THREADS # libusb
 	select BR2_PACKAGE_LIBUSB
 	select BR2_PACKAGE_LIBGUDEV
+	select BR2_PACKAGE_LIBICONV if !BR2_ENABLE_LOCALE
 	help
 	  HIDAPI is a multi-platform library which allows an application
 	  to interface with USB and Bluetooth HID-Class devices on

package/hidapi/hidapi.mk

@@ -16,4 +16,9 @@ HIDAPI_LICENSE_FILES = LICENSE.txt LICENSE-gpl3.txt LICENSE-bsd.txt LICENSE-orig
 
 HIDAPI_DEPENDENCIES = libusb libgudev
 
+ifeq ($(BR2_PACKAGE_LIBICONV),y)
+HIDAPI_DEPENDENCIES += libiconv
+HIDAPI_CONF_ENV += LIBS="-liconv"
+endif
+
 $(eval $(autotools-package))