Hack for supporting Boost on Homebrew
Hack to prevent Makefile.config from being regenerated by "make clean"
Add support for using a build directory
Improved support for building JARs
Support specifying a JAR manifest
Fix JAR installation
Don't rely on process substitution
Allow external code using libnixexpr to add types

Code that links to libnixexpr (e.g. plugins loaded with importNative, or
nix-exec) may want to provide custom value types and operations on
values of those types. For example, nix-exec is currently using sets
where a custom IO value type would be more appropriate. This commit
provides a generic hook for such types in the form of tExternal and the
ExternalBase virtual class, which contains all functions necessary for
libnixexpr's type-polymorphic functions (e.g. `showType`) to be
implemented.
Make all ExternalValueBase functions const
Merge pull request #401 from shlevy/external-value

Allow external code using libnixexpr to add types
Fix another operator precedence issue found by Perl 5.20
Shut up a warning
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...)
Define ‘environ’

http://hydra.nixos.org/build/17690555
Remove some platforms with too-old compilers
Remove Fedora 18, 19 builds

http://hydra.nixos.org/build/17703462
Explicitly include required C headers
Set custom compiler flags on Cygwin
Fix library handling on Cygwin

1. Shared lib extension is .dll
2. Shared libs are installed to $(prefix)/bin
3. Linker does not support -z flag
Link against perl.dll on Cygwin