Add compiler and linker flags for MIPS.

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index dcd5d6596d619d40e2389f20f7fee94cdd351694..b5c6fe3e57ffb27bb7e1d72711e744dbf20cfc5c 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -6,6 +6,9 @@ import("//build/config/android/config.gni")
 if (cpu_arch == "arm") {
   import("//build/config/arm.gni")
 }
+if (cpu_arch == "mipsel" || cpu_arch == "mips64el") {
+  import("//build/config/mips.gni")

[wtc, 2015/01/07 23:56:35]

I decided to add build/config/mips.gni and declare the buildvariable
mips_arch_variant there because I found third_party/webrtc already declares that
buildvariable. It is best to declare that variable in a .gni file. Apparently
webrtc doesn't import build/config/compiler/BUILD.gn.

The companion webrtc CL is https://webrtc-codereview.appspot.com/41399004/

+}
 if (is_posix) {
   import("//build/config/gcc/gcc_version.gni")
 }
@@ -271,6 +274,51 @@ config("compiler") {
           ]
         }
       }
+    } else if (cpu_arch == "mipsel") {
+      # Don't set the compiler flags for the WebView build. These will come
+      # from the Android build system.
+      if (!is_android_webview_build) {
+        if (mips_arch_variant == "r6") {
+          cflags += [
+            "-mips32r6",
+            "-Wa,-mips32r6",
+          ]
+          if (is_android) {
+            ldflags += [
+              "-mips32r6",
+              "-Wl,-melf32ltsmip",
+            ]
+          }
+        } else if (mips_arch_variant == "r2") {
+          cflags += [
+            "-mips32r2",
+            "-Wa,-mips32r2",
+          ]
+        } else if (mips_arch_variant == "r1") {
+          cflags += [
+            "-mips32",
+            "-Wa,-mips32",
+          ]
+        }
+      }
+    } else if (cpu_arch == "mips64el") {
+      # Don't set the compiler flags for the WebView build. These will come
+      # from the Android build system.
+      if (!is_android_webview_build) {
+        if (mips_arch_variant == "r6") {
+          cflags += [
+            "-mips64r6",
+            "-Wa,-mips64r6",
+          ]
+          ldflags += [ "-mips64r6" ]
+        } else if (mips_arch_variant == "r2") {
+          cflags += [
+            "-mips64r2",
+            "-Wa,-mips64r2",
+          ]
+          ldflags += [ "-mips64r2" ]
+        }
+      }
     }
 
     defines += [ "_FILE_OFFSET_BITS=64" ]