gnu: efl: Fix build on 32-bit architectures.

* gnu/packages/patches/efl-mesa-compat.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/enlightenment.scm (efl)[source](patches): Use it.

gnu/local.mk

@@ -659,6 +659,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/doxygen-test.patch			\
   %D%/packages/patches/dropbear-CVE-2018-15599.patch		\
   %D%/packages/patches/dvd+rw-tools-add-include.patch 		\
+  %D%/packages/patches/efl-mesa-compat.patch			\
   %D%/packages/patches/elfutils-tests-ptrace.patch		\
   %D%/packages/patches/einstein-build.patch			\
   %D%/packages/patches/emacs-exec-path.patch			\

gnu/packages/enlightenment.scm

@@ -70,6 +70,7 @@
               (uri (string-append
                     "https://download.enlightenment.org/rel/libs/efl/efl-"
                     version ".tar.xz"))
+              (patches (search-patches "efl-mesa-compat.patch"))
               (sha256
                (base32
                 "0a5907h896pvpix7a6idc2fspzy6d78xrzf84k8y9fyvnd14nxs4"))))

gnu/packages/patches/efl-mesa-compat.patch

@@ -0,0 +1,21 @@
+Fix build on 32-bit architectures with Mesa 18.3.  Patch taken from upstream:
+
+https://git.enlightenment.org/core/efl.git/commit/?id=0d2b624f1e24240a1c4e651aa1cfe9a8dd10a573
+
+diff --git a/src/lib/evas/Evas_GL.h b/src/lib/evas/Evas_GL.h
+index b6b642400f..4f67b1695f 100644
+--- a/src/lib/evas/Evas_GL.h
++++ b/src/lib/evas/Evas_GL.h
+@@ -4272,9 +4272,11 @@ typedef signed int       GLfixed;      // Changed khronos_int32_t
+ 
+ #ifndef GL_ES_VERSION_2_0
+ /* GL types for handling large vertex buffer objects */
+-#include <stddef.h>
++# ifndef GL_VERSION_1_5
++#  include <stddef.h>
+ typedef ptrdiff_t GLintptr;     // Changed khronos_intptr_t
+ typedef ptrdiff_t GLsizeiptr;   // Changed khronos_ssize_t
++# endif
+ #endif
+ 
+ /* Some definitions from GLES 3.0.