Add pkg-config gc flags to llvm Makefile

This makes building work for systems which have gc installed in a
non-standard location.  The invocation was pulled from
https://github.com/schani/clojurec/pull/2, and then modified based on
https://github.com/idris-lang/Idris-dev/pull/428#issuecomment-26302460.
Unbreak windows build of idris_net.c
Add decision procedure for Prelude.Nat.LTE
Merge pull request #1319 from Melvar/decide-LTE

Add decision procedure for Prelude.Nat.LTE
Merge pull request #1317 from melted/net_fix

Unbreak windows build of idris_net.c
Make type arguments in (=) declaration implicit (for docs)
Parenthasize infix names in REPL output
Merge pull request #1322 from bmsherman/equalDecl

Make type arguments in (=) declaration implicit (for docs)
Proper and complete parenthasization of infix operator names.
Merge branch 'master' into parenthasizeInfix

Conflicts:
	src/Idris/REPL.hs
Merge pull request #1323 from bmsherman/parenthasizeInfix

Parenthasize infix names in REPL output
Improvements to :search, primarily in handling typeclasses
Ignore default class methods in :search
fix spelling of "parenthesise"

Signed-off-by: Ricky Elrod <ricky@elrod.me>
Merge pull request #1326 from CodeBlock/spellingfix

fix spelling of "parenthesise"
Merge pull request #1324 from bmsherman/improvedSearch

Improvements to :search, primarily in handling typeclasses
Support builds that doesn't use cabal for libs and rts
data-lens is not a dep of idris

lens is, but that isn't available in the binary repos of the old version
of Ubuntu Travis-CI runs.
Parsing for quasiquotes
Elaborate quasiquotes