gnu: Add aws-c-event-stream.

* gnu/packages/c.scm (aws-c-event-stream): New variable.
* gnu/packages/patches/aws-c-event-stream-cmake-prefix.patch:
New file.
* gnu/local.mk (dist_patch_DATA): Add it.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/local.mk

@@ -823,6 +823,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/avogadro-python-eigen-lib.patch		\
   %D%/packages/patches/avidemux-install-to-lib.patch		\
   %D%/packages/patches/awesome-reproducible-png.patch		\
+  %D%/packages/patches/aws-c-event-stream-cmake-prefix.patch  \
   %D%/packages/patches/aws-checksums-cmake-prefix.patch		\
   %D%/packages/patches/azr3.patch				\
   %D%/packages/patches/bash-reproducible-linux-pgrp-pipe.patch	\

gnu/packages/c.scm

@@ -584,3 +584,30 @@ (define-public aws-checksums
 with fallback to efficient C99 software implementations.")
     (home-page "https://github.com/awslabs/aws-checksums")
     (license license:asl2.0)))
+
+(define-public aws-c-event-stream
+  (package
+    (name "aws-c-event-stream")
+    (version "0.1.6")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url (string-append "https://github.com/awslabs/" name))
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "1vl9ainc4klv0g9gk1iv4833bsllni6jxn6mwb0fnv2dnlz7zv9q"))
+              (patches (search-patches "aws-c-event-stream-cmake-prefix.patch"))))
+    (build-system cmake-build-system)
+    (propagated-inputs
+     `(("aws-c-common" ,aws-c-common)))
+    (inputs
+     `(("aws-checksums" ,aws-checksums)))
+    (synopsis "Amazon Web Services client-server message format library")
+    (description
+     "This library is a C99 implementation for @acronym{AWS,Amazon Web Services}
+event stream encoding, a binary format for bidirectional client-server
+communication.")
+    (home-page "https://github.com/awslabs/aws-c-event-stream")
+    (license license:asl2.0)))

gnu/packages/patches/aws-c-event-stream-cmake-prefix.patch

@@ -0,0 +1,13 @@
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -3,6 +3,10 @@
+ cmake_minimum_required (VERSION 3.1)
+ project (aws-c-event-stream C)
+ 
++if (DEFINED ENV{CMAKE_PREFIX_PATH})
++    set(CMAKE_PREFIX_PATH $ENV{CMAKE_PREFIX_PATH})
++endif()
++
+ if (DEFINED CMAKE_PREFIX_PATH)
+     file(TO_CMAKE_PATH "${CMAKE_PREFIX_PATH}" CMAKE_PREFIX_PATH)
+ endif()