Use -mthumb on debug build too.

Review URL: http://codereview.chromium.org/57056

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1654 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

SConstruct

@@ -92,7 +92,10 @@ LIBRARY_FLAGS = {
     },
     'mode:debug': {
       'CCFLAGS':      ['-g', '-O0'],
-      'CPPDEFINES':   ['ENABLE_DISASSEMBLER', 'DEBUG']
+      'CPPDEFINES':   ['ENABLE_DISASSEMBLER', 'DEBUG'],
+      'os:android': {
+        'CCFLAGS':    ['-mthumb']
+      }
     },
     'mode:release': {
       'CCFLAGS':      ['-O3', '-fomit-frame-pointer', '-fdata-sections',