Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20200330' into staging

Improve PIE and other linkage
Fix for decodetree vs Python3 floor division operator
Fix i386 INDEX_op_dup2_vec expansion
Fix loongson multimedia condition instructions

# gpg: Signature made Tue 31 Mar 2020 04:50:15 BST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-tcg-20200330:
  decodetree: Use Python3 floor division operator
  tcg/i386: Fix INDEX_op_dup2_vec
  target/mips: Fix loongson multimedia condition instructions
  configure: Support -static-pie if requested
  configure: Override the os default with --disable-pie
  configure: Unnest detection of -z,relro and -z,now
  configure: Always detect -no-pie toolchain support
  configure: Do not force pie=no for non-x86
  tcg: Remove softmmu code_gen_buffer fixed address
  configure: Drop adjustment of textseg

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>