Remove an obsolete ARM gdb hack.

Experiment shows that the claim in the makefile was false: gdb works fine
setting breakpoints in these functions when compiled without special treatment.

Change-Id: Ibdf4dd5a14d171c954b8c2089daaf28e1c310be9
diff --git a/libc/Android.mk b/libc/Android.mk
index df9805a..116e08f 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -414,23 +414,6 @@
     upstream-netbsd/libc/string/strxfrm.c \
     upstream-netbsd/libc/unistd/killpg.c \
 
-# These files need to be arm so that gdbserver
-# can set breakpoints in them without messing
-# up any thumb code.
-# TODO: is this actually necessary?
-ifeq ($(TARGET_ARCH),arm)
-libc_common_src_files += \
-    bionic/pthread-atfork.c.arm \
-    bionic/pthread-rwlocks.c.arm \
-    bionic/pthread-timers.c.arm \
-    bionic/ptrace.c.arm \
-
-libc_static_common_src_files += \
-    bionic/pthread.c.arm \
-    bionic/pthread_create.cpp.arm \
-    bionic/pthread_key.cpp.arm \
-
-else
 libc_common_src_files += \
     bionic/pthread-atfork.c \
     bionic/pthread-rwlocks.c \
@@ -442,9 +425,6 @@
     bionic/pthread_create.cpp \
     bionic/pthread_key.cpp \
 
-endif # arm
-
-
 # Architecture specific source files go here
 # =========================================================
 ifeq ($(TARGET_ARCH),arm)