qemu: port musl patch to new version (#46449)

pkgs/applications/virtualization/qemu/default.nix

···
       url = https://raw.githubusercontent.com/alpinelinux/aports/2bb133986e8fa90e2e76d53369f03861a87a74ef/main/qemu/musl-F_SHLCK-and-F_EXLCK.patch;
       sha256 = "1gm67v41gw6apzgz7jr3zv9z80wvkv0jaxd2w4d16hmipa8bhs0k";
     })
-    (fetchpatch {
-      url = https://raw.githubusercontent.com/alpinelinux/aports/61a7a1b77a868e3b940c0b25e6c2b2a6c32caf20/main/qemu/0006-linux-user-signal.c-define-__SIGRTMIN-MAX-for-non-GN.patch;
-      sha256 = "1ar6r1vpmhnbs72v6mhgyahcjcf7b9b4xi7asx17sy68m171d2g6";
-    })
+    ./sigrtminmax.patch
     (fetchpatch {
       url = https://raw.githubusercontent.com/alpinelinux/aports/2bb133986e8fa90e2e76d53369f03861a87a74ef/main/qemu/fix-sigevent-and-sigval_t.patch;
       sha256 = "0wk0rrcqywhrw9hygy6ap0lfg314m9z1wr2hn8338r5gfcw75mav";

pkgs/applications/virtualization/qemu/sigrtminmax.patch

···
+From 2697fcc42546e814a2d2617671cb8398b15256fb Mon Sep 17 00:00:00 2001
+From: Will Dietz <[e-mail]>
+Date: Fri, 17 Aug 2018 00:22:35 -0500
+Subject: [PATCH] quick port __SIGRTMIN/__SIGRTMAX patch for qemu 3.0
+
+---
+ linux-user/signal.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/linux-user/signal.c b/linux-user/signal.c
+index 602b631b92..87f9240134 100644
+--- a/linux-user/signal.c
++++ b/linux-user/signal.c
+@@ -26,6 +26,13 @@
+ #include "trace.h"
+ #include "signal-common.h"
+ 
++#ifndef __SIGRTMIN
++#define __SIGRTMIN 32
++#endif
++#ifndef __SIGRTMAX
++#define __SIGRTMAX (NSIG-1)
++#endif
++
+ struct target_sigaltstack target_sigaltstack_used = {
+     .ss_sp = 0,
+     .ss_size = 0,
+-- 
+2.18.0
+