$ powerpc-linux-gnu-cpp -dM -x c /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 1
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ arm-linux-gnueabi-cpp -dM -x c /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_ATOMIC_CHAR_LOCK_FREE 1
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 1
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 1
#define __GCC_ATOMIC_POINTER_LOCK_FREE 1
#define __GCC_ATOMIC_INT_LOCK_FREE 1
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 1
#define __GCC_ATOMIC_LONG_LOCK_FREE 1
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 1
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 1
#define __GCC_ATOMIC_SHORT_LOCK_FREE 1
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ arm-linux-gnueabi-cpp -dM -x c -march=armv7-a /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ cpp -dM -x c /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_HLE_ACQUIRE 65536
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ i686-linux-gnu-cpp -dM -x c /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_HLE_ACQUIRE 65536
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ i686-w64-mingw32-cpp -dM -x c /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_HLE_ACQUIRE 65536
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ powerpc-rtems5-cpp -dM -x c /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 1
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ i386-rtems5-cpp -dM -x c -march=i386 /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_ATOMIC_CHAR_LOCK_FREE 1
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 1
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 1
#define __GCC_ATOMIC_POINTER_LOCK_FREE 1
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_HLE_ACQUIRE 65536
#define __GCC_ATOMIC_INT_LOCK_FREE 1
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 1
#define __GCC_ATOMIC_LONG_LOCK_FREE 1
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 1
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 1
#define __GCC_ATOMIC_SHORT_LOCK_FREE 1
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ i386-rtems5-cpp -dM -x c -march=i686 /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_HLE_ACQUIRE 65536
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

$ aarch64-linux-cpp -dM -x c /dev/null |egrep 'ATOMIC|SYNC'
#define __ATOMIC_ACQUIRE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __SIG_ATOMIC_TYPE__ int
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_SEQ_CST 5
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3