arm: Add thumb target and associated fixes

skia/skia.gyp

Index: skia/skia.gyp
diff --git a/skia/skia.gyp b/skia/skia.gyp
index 97dcd35920698a842743099ff02ecb54bbf9f95c..ab8d35e25169cfc9b17bf08243a02b7747b69769 100644
--- a/skia/skia.gyp
+++ b/skia/skia.gyp
@@ -576,16 +576,13 @@
         [ 'OS != "win"', {
           'sources/': [ ['exclude', '_win\\.(cc|cpp)$'] ],
         }],
-        [ 'target_arch == "arm" and armv7 == 1', {
+        [ 'armv7 == 1', {
           'defines': [
             '__ARM_HAVE_NEON',
             '__ARM_ARCH__=7',
           ],
-          'cflags!': [
-            # These files contain ARM assembly, and building with thumb breaks
-            # the assembler.
-            '-mthumb',
-          ],
+        }],
+        [ 'target_arch == "arm"', {
           'sources!': [
             '../third_party/skia/src/opts/opts_check_SSE2.cpp'
           ],