Remove workarounds for old versions of clang and GCC.

Bug: N/A
Test: ran tests
Change-Id: I89d224c743f5113771de41c74161a7a5ccad05e4

libc/arch-arm/bionic/__aeabi.c

@@ -26,13 +26,11 @@
  * SUCH DAMAGE.
  */
 
-#if defined(__clang__)
 // clang interprets -fno-builtin more loosely than you might expect,
 // and thinks it's okay to still substitute builtins as long as they're
 // named __aeabi_* rather than __builtin_*, which causes infinite
 // recursion if we have the fortified memcpy visible in this file.
 #undef _FORTIFY_SOURCE
-#endif
 
 #include <stddef.h>
 #include <string.h>

tests/atexit_test.cpp

@@ -14,17 +14,7 @@
  * limitations under the License.
  */
 
-// To work around b/25643775, we disable clang optimization so that
-//   VTT for std::__1::basic_stringstream<char, std::__1::char_traits<char>,
-//   std::__1::allocator<char> >
-// will be correctly kept for other module's references.
-#if defined(__clang__) && (defined(__arm__) || defined(__aarch64__))
-#pragma clang optimize off
-#endif
 #include <gtest/gtest.h>
-#if defined(__clang__) && (defined(__arm__) || defined(__aarch64__))
-#pragma clang optimize on
-#endif
 
 #include <dlfcn.h>
 #include <libgen.h>

tests/thread_local_test.cpp

@@ -18,14 +18,6 @@
 #include <stdint.h>
 #include <string.h>
 
-#if defined(__GNUC__) && !defined(__clang__) && \
-    (defined(__arm__) || defined(__aarch64__))
-// Gcc has a bug with -O -fdata-section for the arm target: http://b/22772147.
-// Until that bug is fixed, disable optimization since
-// it is not essential for this test.
-#pragma GCC optimize("-O0")
-#endif
-
 __thread int local_var = 100;
 int shared_var = 200;