Use GCC for Linux ANGLE builds

scripts/build-linux-static-graphics.sh

@@ -195,9 +195,9 @@ target_os = "linux"
 target_cpu = "$TARGET_CPU"
 is_debug = false
 is_component_build = false
-is_clang = true
-clang_base_path = "/usr"
-clang_use_chrome_plugins = false
+is_clang = false
+cc = "gcc"
+cxx = "g++"
 use_custom_libcxx = false
 use_sysroot = false
 use_lld = false