package/dlib: add missing dependency on wchar

Since the package was introduced in Buildroot commit
3cb185d3df237341382b03c8e6f6c5358063c721, it has been failing to build
on !wchar configurations. Let's add the missing dependency on wchar
support.

Fixes:

  https://autobuild.buildroot.org/results/f5c543bcf57181373680d0c16a1814d21b000bcf

Signed-off-by: Roy Kollen Svendsen <roykollensvendsen@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/dlib/Config.in

@@ -2,6 +2,7 @@ config BR2_PACKAGE_DLIB
 	bool "dlib"
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_TOOLCHAIN_HAS_THREADS
+	depends on BR2_USE_WCHAR
 	help
 	  Dlib is a modern C++ toolkit containing machine learning
 	  algorithms and tools for creating complex software in C++ to
@@ -9,6 +10,7 @@ config BR2_PACKAGE_DLIB
 
 	  http://dlib.net
 
-comment "dlib needs a toolchain w/ C++, threads"
+comment "dlib needs a toolchain w/ C++, threads, wchar"
 	depends on !BR2_INSTALL_LIBSTDCPP || \
-		!BR2_TOOLCHAIN_HAS_THREADS
+		!BR2_TOOLCHAIN_HAS_THREADS || \
+		!BR2_USE_WCHAR