Use posix_spawn to run the pager

In low memory environments, "nix-env -qa" failed because the fork to
run the pager hit the kernel's overcommit limits. Using posix_spawn
gets around this. (Actually, you have to use posix_spawn with the
undocumented POSIX_SPAWN_USEVFORK flag, otherwise it just uses
fork/exec...)

1 files changed, 1 insertions, 0 deletions

diff --git a/src/libutil/types.hh b/src/libutil/types.hh
index 160884ee1ad7..030996a060e2 100644
--- a/src/libutil/types.hh
+++ b/src/libutil/types.hh
@@ -73,6 +73,7 @@ class SysError : public Error
 public:
     int errNo;
     SysError(const FormatOrString & fs);
+    SysError(int errNo, const FormatOrString & fs);
 };