nix: fix for glibc 2.26 and fix primary groups of nixbldN users.

srcpkgs/nix/template

@@ -1,7 +1,7 @@
 # Template file for 'nix'
 pkgname=nix
 version=1.11.4
-revision=3
+revision=4
 build_style=gnu-configure
 # Use /nix/var as suggested by the official Manual.
 configure_args="--localstatedir=/nix/var"
@@ -14,8 +14,7 @@ makedepends="bzip2-devel gc-devel libcurl-devel liblzma-devel libressl-devel
 conf_files="/etc/nix/nix.conf"
 # Create required build users/groups.
 system_groups="nixbld"
-system_accounts="nixbld1"
-for f in {2..9}; do
+for f in {1..9}; do
 	system_accounts+=" nixbld${f}"
 	eval export nixbld\${f}_pgroup="nixbld"
 done
@@ -39,6 +38,7 @@ distfiles="http://nixos.org/releases/nix/nix-${version}/nix-${version}.tar.xz"
 checksum=937779ed2efaa3dec210250635401980acb99a6fea6d7374fbaea78231b36d34
 
 pre_configure() {
+	sed -i 's/ucontext/struct ucontext_t/g' src/libmain/stack.cc
 	sed -i '/^CFLAGS=/d;/^CXXFLAGS=/d' configure
 	echo "GLOBAL_LDFLAGS += $LDFLAGS" >>mk/lib.mk
 }