Enable cross compile to android from mac.

build/toolchain/linux/BUILD.gn

Index: build/toolchain/linux/BUILD.gn
diff --git a/build/toolchain/linux/BUILD.gn b/build/toolchain/linux/BUILD.gn
index 7bcd9d01170e5a5a86d53e4fd69ef78eccae712c..15ad5bdea8c6beb5d8bbe456379bc33185f73dd5 100644
--- a/build/toolchain/linux/BUILD.gn
+++ b/build/toolchain/linux/BUILD.gn
@@ -23,6 +23,8 @@ gcc_toolchain("arm") {
 
   ar = "arm-linux-gnueabi-ar"
   ld = cxx
+  readelf = "arm-linux-gnueabi-readelf"
+  nm = "arm-linux-gnueabi-nm"
 
   toolchain_cpu = "arm"
   toolchain_os = "linux"
@@ -39,7 +41,8 @@ gcc_toolchain("clang_x86") {
   }
   cc = "${compiler_prefix}$prefix/clang"
   cxx = "${compiler_prefix}$prefix/clang++"
-
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
@@ -52,6 +55,8 @@ gcc_toolchain("x86") {
   cc = "${compiler_prefix}gcc"
   cxx = "$compiler_prefix}g++"
 
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
@@ -71,6 +76,8 @@ gcc_toolchain("clang_x64") {
   cc = "${compiler_prefix}$prefix/clang"
   cxx = "${compiler_prefix}$prefix/clang++"
 
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
@@ -83,6 +90,8 @@ gcc_toolchain("x64") {
   cc = "${compiler_prefix}gcc"
   cxx = "${compiler_prefix}g++"
 
+  readelf = "readelf"
+  nm = "nm"
   ar = "ar"
   ld = cxx
 
@@ -96,6 +105,8 @@ gcc_toolchain("mipsel") {
   cxx = "mipsel-linux-gnu-g++"
   ar = "mipsel-linux-gnu-ar"
   ld = cxx
+  readelf = "mipsel-linux-gnu-readelf"
+  nm = "mipsel-linux-gnu-nm"
 
   toolchain_cpu = "mipsel"
   toolchain_os = "linux"