Merge #28536: libsigsegv: add enableSigbusFix option

(It's partially changed version of the PR.)

pkgs/development/libraries/libsigsegv/2.5.nix

@@ -1,4 +1,6 @@
-{ stdenv, fetchurl }:
+{ stdenv, fetchurl
+, enableSigbusFix ? false # required by kernels < 3.18.6
+}:
 
 stdenv.mkDerivation rec {
   name = "libsigsegv-2.5";
@@ -8,6 +10,8 @@ stdenv.mkDerivation rec {
     sha256 = "0fvcsq9msi63vrbpvks6mqkrnls5cfy6bzww063sqhk2h49vsyyg";
   };
 
+  patches = stdenv.lib.optional enableSigbusFix ./sigbus_fix.patch;
+
   meta = {
     homepage = http://libsigsegv.sf.net;
     description = "A library for handling page faults in user mode";

pkgs/development/libraries/libsigsegv/default.nix

@@ -1,5 +1,6 @@
 { stdenv, fetchurl
 , buildPlatform, hostPlatform
+, enableSigbusFix ? false # required by kernels < 3.18.6
 }:
 
 stdenv.mkDerivation rec {
@@ -10,6 +11,8 @@ stdenv.mkDerivation rec {
     sha256 = "063swdvq7mbmc1clv0rnh20grwln1zfc2qnm0sa1hivcxyr2wz6x";
   };
 
+  patches = if enableSigbusFix then [ ./sigbus_fix.patch ] else null;
+
   doCheck = hostPlatform == buildPlatform;
 
   meta = {

pkgs/development/libraries/libsigsegv/sigbus_fix.patch

@@ -0,0 +1,8 @@
+--- a/src/signals.h	2017-08-23 14:07:05.000000000 +0100
++++ b/src/signals.h	2017-08-23 14:06:53.000000000 +0100
+@@ -18,4 +18,4 @@
+ /* List of signals that are sent when an invalid virtual memory address
+    is accessed, or when the stack overflows.  */
+ #define SIGSEGV_FOR_ALL_SIGNALS(var,body) \
+-  { int var; var = SIGSEGV; { body } }
++  { int var; var = SIGSEGV; { body } var = SIGBUS; { body } }