Fix: tls-compat.h exposes compiler-dependent public configuration
Exposing the storage class chosen by ax_tls.m4 in a public header is
a bad idea, because if a recent gcc is used when configuring
liburcu, thus detecting C11, it will choose _Thread_local. Then, if an
external project uses urcu/tls-compat.h with an older gcc (e.g. 4.8),
it will fail to build, because that storage class is unknown, and
__thread should be used instead.
Therefore, use a preprocessor conditional on __cplusplus to detect C++11
(and use thread_local). Else, the STDC version is used to select
_Thread_local. Else check if _MSC_VER is defined to select
__declspec(thread), or else rely on __thread as fallback.
On architectures where "char" is signed, it should be cast to unsigned
char before being passed as parameter to isdigit or isspace. Based on
their man page:
These functions check whether c, which must have the value of an
unsigned char or EOF, falls into a certain character class according to
the specified locale.
Passing a signed char as parameter is invalid if the values fall into
the negative range of the signed char.
Cleanup: update code layout to fix old gcc warning
Some CI jobs show:
urcu-pointer.o
13:46:22 In file included from urcu.c:49:0:
13:46:22 urcu-wait.h:70:9: warning: missing initializer for field 'lock' of 'struct cds_wfs_stack' [-Wmissing-field-initializers]
13:46:22 struct urcu_wait_queue name = URCU_WAIT_QUEUE_HEAD_INIT(name)
13:46:22 ^
13:46:22 urcu.c:150:8: note: in expansion of macro 'DEFINE_URCU_WAIT_QUEUE'
13:46:22 static DEFINE_URCU_WAIT_QUEUE(gp_waiters);
13:46:22 ^
13:46:22 In file included from urcu-wait.h:27:0,
13:46:22 from urcu.c:49:
13:46:22 ../include/urcu/wfstack.h:92:18: note: 'lock' declared here
13:46:22 pthread_mutex_t lock;
13:46:22
