dev-util/mingw64-runtime: filter LDFLAGS for hash style

dev-util/mingw64-runtime: filter LDFLAGS for hash style

Normally mingw-64 does not use dynamic linker.
One exception is at ./configure time where $LDFLAGS
is used by default.

When LDFFLAGS=-Wl,--hash-style=gnu is passed (default
on linux) to mingw64-runtime a few things are not
auto-detected. One of them is  __CTORS_LIST__ / __DTORS_LIST__
support by binutils' target ld.

If constructors are not provided then binaries start
crashing at shutdown.

The workaround is to filter out -Wl,--hash-style=* options.

Longer-term fix will be to install mingw64-runtime into
target: bug #642604. That wa LDFLAGS from CBUILD will not
leak into libc packages.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Package-Manager: Portage-2.3.50, Repoman-2.3.11