Add support for the Sun linker. Fixes joyent/pkgsrc/issues/455 on SunOS.

Based on jcea's pull request.

multimedia/x265/distinfo

@@ -1,6 +1,7 @@
-$NetBSD: distinfo,v 1.15 2017/01/01 16:31:44 adam Exp $
+$NetBSD: distinfo,v 1.16 2017/02/13 13:39:55 fhajny Exp $
 
 SHA1 (x265_2.2.tar.gz) = 709ddcf639b414c65867683419de82bc34b587ca
 RMD160 (x265_2.2.tar.gz) = 5bc6e69601752f9ef7a8b80989f48767dfecab10
 SHA512 (x265_2.2.tar.gz) = 335bb38cf0892f2c4310033b076d51115c0b7faa9596a4f556dde5e3d1378d04f3d0055cb0bf2441eb725b7f84c246174bdc315eeb4ddde61ef9d79469f44eef
 Size (x265_2.2.tar.gz) = 1203801 bytes
+SHA1 (patch-CMakeLists.txt) = fbf4d08133a48b342a060f1b45bab0253455a1b1

multimedia/x265/patches/patch-CMakeLists.txt

@@ -0,0 +1,24 @@
+$NetBSD: patch-CMakeLists.txt,v 1.1 2017/02/13 13:39:55 fhajny Exp $
+
+Solaris ld: Provided assembler is not PIC, so we pass "-mimpure-text"
+            to the compiler so it doesn't send "-ztext" to ld.
+
+Solaris ld: Passing "-Wa,--noexecstack" to gcc will generate an ELF section
+            requesting a non executable stack. I don't know if Solaris ld
+            is complying or just ignoring it.
+
+--- CMakeLists.txt.OLD	2017-01-27 02:42:21.295232904 +0000
++++ CMakeLists.txt	2017-01-27 02:51:32.144600352 +0000
+@@ -523,7 +523,11 @@
+         elseif(CYGWIN)
+             # Cygwin is not officially supported or tested. MinGW with msys is recommended.
+         else()
+-            list(APPEND LINKER_OPTIONS "-Wl,-Bsymbolic,-znoexecstack")
++            if(${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
++                list(APPEND LINKER_OPTIONS "-mimpure-text -Wa,--noexecstack")
++            else()
++                list(APPEND LINKER_OPTIONS "-Wl,-Bsymbolic,-znoexecstack")
++            endif()
+         endif()
+     endif()
+     set_target_properties(x265-shared PROPERTIES SOVERSION ${X265_BUILD})