gn: Drop NaCl gcc-newlib toolchains

NaCl's gcc-newlib toolchains are no longer supported and should never
be used in bot builds at this point.  The newlib use cases are now
supported by the nacl-clang toolchain.  The gcc-glibc toolchains
remain as they were.

R=dpranke@chromium.org, dschuff@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1350093002

Cr-Original-Commit-Position: refs/heads/master@{#349478}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 5927063a80783f2873f6be1e5948d9382028fff3

toolchain/nacl/BUILD.gn

@@ -17,55 +17,12 @@ os_toolchain_dir = "${nacl_toolchain_dir}/${current_os}_x86"
 # single batch to amortize python startup, etc.
 revisions = exec_script("//native_client/build/get_toolchain_revision.py",
                         [
-                          "nacl_arm_newlib",
-                          "nacl_x86_newlib",
                           "nacl_x86_glibc",
                           "pnacl_newlib",
                         ],
                         "trim list lines")
-nacl_arm_newlib_rev = revisions[0]
-nacl_x86_newlib_rev = revisions[1]
-nacl_x86_glibc_rev = revisions[2]
-pnacl_newlib_rev = revisions[3]
-
-nacl_toolchain("newlib_arm") {
-  toolchain_package = "nacl_arm_newlib"
-  toolchain_revision = nacl_arm_newlib_rev
-  toolchain_cpu = "arm"
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/arm-nacl-"
-  is_clang = false
-
-  cc = toolprefix + "gcc"
-  cxx = toolprefix + "g++"
-  ar = toolprefix + "ar"
-  ld = cxx
-}
-
-nacl_toolchain("newlib_x86") {
-  toolchain_package = "nacl_x86_newlib"
-  toolchain_revision = nacl_x86_newlib_rev
-  toolchain_cpu = "x86"
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/i686-nacl-"
-  is_clang = false
-
-  cc = toolprefix + "gcc"
-  cxx = toolprefix + "g++"
-  ar = toolprefix + "ar"
-  ld = cxx
-}
-
-nacl_toolchain("newlib_x64") {
-  toolchain_package = "nacl_x86_newlib"
-  toolchain_revision = nacl_x86_newlib_rev
-  toolchain_cpu = "x64"
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/x86_64-nacl-"
-  is_clang = false
-
-  cc = toolprefix + "gcc"
-  cxx = toolprefix + "g++"
-  ar = toolprefix + "ar"
-  ld = cxx
-}
+nacl_x86_glibc_rev = revisions[0]
+pnacl_newlib_rev = revisions[1]
 
 nacl_toolchain("newlib_pnacl") {
   toolchain_package = "pnacl_newlib"