meson: Correctly locate libc++

The meson find_library() function takes a library name without the "lib"
prefix. Its usage to find lic++ is thus not correct, and meson warns
about it:

WARNING: find_library('libc++') starting in "lib" only works by accident and is not portable

Fix it by dropping the "lib" prefix.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

meson.build

@@ -109,7 +109,7 @@ if cc.get_id() == 'clang'
 
     # Use libc++ by default if available instead of libstdc++ when compiling
     # with clang.
-    if cc.find_library('libc++', required : false).found()
+    if cc.find_library('c++', required : false).found()
         cpp_arguments += [
             '-stdlib=libc++',
         ]