xf86-video-vmware: add libstdc++ to depends

[flexibeast]

A Reddit user found that X using xf86-video-vmware wouldn't start without manually installing the libstdc++ package. This PR adds that package to xf86-video-vmware's 'depends'.

[Hoshpak]

The screenshot looks more like libllvm9 should depend on libstdc++ rather than the driver package itself or what do you think @q66 ?

[q66]

libllvm9 already shlib-requires it, so the user just has a broken system

q66@rimi: /home/q66$ xbps-query libllvm9
architecture: ppc64le
automatic-install: yes
build-date: 2019-10-05 22:14 CEST
filename-sha256: c525f9332dbd805394cc2e5360c080fc12bc7baa9c4a2e121679ef7b2b5f40e1
filename-size: 19MB
homepage: https://www.llvm.org
install-date: 2019-10-19 19:23 CEST
installed_size: 87MB
license: NCSA
maintainer: q66 <daniel@octaforge.org>
metafile-sha256: 8b5f270ecb5a3ad7f64c46a415a8c3820d9a7a581dcdf2c7ad109320444edab2
pkgver: libllvm9-9.0.0_2
repository: /media/hostdir/binpkgs
shlib-provides:
	libLLVM-9.so
shlib-requires:
	libffi.so.6
	libedit.so.0
	libz.so.1
	libdl.so.2
	libncursesw.so.6
	libpthread.so.0
	libxml2.so.2
	libstdc++.so.6
	libm.so.6
	libgcc_s.so.1
	libc.so.6
	ld64.so.2
short_desc: Low Level Virtual Machine - runtime library
state: installed

[Hoshpak]

Alright then, let's close.