x86: fix full_x86-eng build

The latest merge conflict resolution worked only for ARM, but not for x86
Both ARM and x86 builds have been tested with this fix.

Change-Id: I4ec1f1b0ea32fa86e7e2515b221133473d6550a3
NOTE: Care has been taken to not change the compiler flags for ARM builds.
      In particular, when building crtbegin_so.so, the -fPIC flag is only
      used for x86 (previous reports indicate that it breaks the ARM
      build at runtime for obscure reasons).
diff --git a/libc/arch-x86/bionic/crtend.S b/libc/arch-x86/bionic/crtend.S
index 884ba8b..68447e7 100644
--- a/libc/arch-x86/bionic/crtend.S
+++ b/libc/arch-x86/bionic/crtend.S
@@ -6,3 +6,10 @@
 
 	.section .fini_array, "aw"
 	.long 0
+
+	.section	.eh_frame,"a",@progbits
+	.align 4
+	.type	__FRAME_END__, @object
+	.size	__FRAME_END__, 4
+__FRAME_END__:
+	.zero	4