gnu: snappy: Optimise.

* gnu/packages/compression.scm (snappy)[source]: Build with ‘-O2’.
* gnu/package/patches/snappy-add-O2-flag-in-CmakeLists.txt.patch:
New file.
* gnu/local.mk (dist_patch_DATA): Add it.

gnu/local.mk

@@ -1138,6 +1138,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/slim-sigusr1.patch			\
   %D%/packages/patches/slim-reset.patch				\
   %D%/packages/patches/slim-login.patch				\
+  %D%/packages/patches/snappy-add-O2-flag-in-CmakeLists.txt.patch	\
   %D%/packages/patches/sooperlooper-build-with-wx-30.patch 	\
   %D%/packages/patches/soundtouch-CVE-2018-14044-14045.patch 	\
   %D%/packages/patches/soundtouch-CVE-2018-1000223.patch 	\

gnu/packages/compression.scm

@@ -1187,14 +1187,15 @@ (define-public snappy
   (package
     (name "snappy")
     (version "1.1.7")
-    (source (origin
-              (method url-fetch)
-              (uri (string-append "https://github.com/google/snappy/archive/"
-                                  version ".tar.gz"))
-              (file-name (string-append "snappy-" version ".tar.gz"))
-              (sha256
-               (base32
-                "1m7rcdqzkys5lspj8jcsaah8w33zh28s771bw0ga2lgzfgl05yix"))))
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "https://github.com/google/snappy/archive/"
+                           version ".tar.gz"))
+       (file-name (string-append "snappy-" version ".tar.gz"))
+       (sha256
+        (base32 "1m7rcdqzkys5lspj8jcsaah8w33zh28s771bw0ga2lgzfgl05yix"))
+       (patches (search-patches "snappy-add-O2-flag-in-CmakeLists.txt.patch"))))
     (build-system cmake-build-system)
     (arguments
      `(#:configure-flags '("-DBUILD_SHARED_LIBS=ON")))

gnu/packages/patches/snappy-add-O2-flag-in-CmakeLists.txt.patch

@@ -0,0 +1,36 @@
+From: Tobias Geerinckx-Rice <me@tobias.gr>
+Date: Sun, 26 Aug 2018 17:24:42 +0200
+Subject: [PATCH] snappy: Add O2 flag in CmakeLists.txt.
+
+Use ‘-O2’ optimisation when building with CMake, as is already done when
+using the Makefile. This patch was copied verbatim from the Snappy
+mailing list[0].
+
+[0]: <snappy-compression@googlegroups.com>
+
+From 903c72fb29b2db07b4abc38a5feb83d88f739d80 Mon Sep 17 00:00:00 2001
+From: huangwenjun <huangwenjun-hf@loongson.cn>
+Date: Fri, 10 Aug 2018 17:17:35 +0800
+Subject: [PATCH] Add O2 optimize flag in CmakeLists.txt.
+
+---
+ CMakeLists.txt | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 62ecd09..29e0cdc 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -6,6 +6,9 @@ set(CMAKE_CXX_STANDARD 11)
+ set(CMAKE_CXX_STANDARD_REQUIRED ON)
+ set(CMAKE_CXX_EXTENSIONS OFF)
+ 
++SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O2")
++SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2")
++
+ # BUILD_SHARED_LIBS is a standard CMake variable, but we declare it here to make
+ # it prominent in the GUI.
+ option(BUILD_SHARED_LIBS "Build shared libraries(DLLs)." OFF)
+-- 
+2.1.0
+