MFH: r341132

• Fix the build with clang and 10+'s ld(1). On the clang side, there's a non-void function missing a return statement and some wrong QString-to-char* casts that had to be fixed. On the linker side, r253839 made our ld stricter, so we had to add some shared libraries that we use since they are not being pulled in indirectly anymore. Based on a patch by Jan Henrik Sylvester <me@janh.de> [1].
• Set LICENSE
• Support staging.
• Remove LATEST_LINK, it is deprecated.
• Use the new OPTIONS helpers for conditional RUN_DEPENDS.

PR: ports/185032 [1]
Submitted by: Jan Henrik Sylvester <me@janh.de> [1]
Approved by: maintainer timeout (37 days)

Approved by: portmgr (antoine)