Remove obsolete -std request.

Bug: http://b/32019064
Test: builds
Change-Id: Id662a63f08054634721750d26e0dcd3c366ed2e6
diff --git a/libm/Android.bp b/libm/Android.bp
index 64d281f..11017f6 100644
--- a/libm/Android.bp
+++ b/libm/Android.bp
@@ -520,7 +520,6 @@
         "-Wno-uninitialized",
         "-Wno-unknown-pragmas",
     ],
-    conlyflags: ["-std=gnu11"],
 
     include_dirs: ["bionic/libc"],
     system_shared_libs: ["libc"],