Fixed wxAtomicInc/Dec() to not use asm/atomic.h header on Linux - it's kernel internal, not available for userspace in newer kernel versions and broken for userspace on some platforms. Use GCC's builtins instead.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48640 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

build/aclocal/atomic_builtins.m4

@@ -0,0 +1,26 @@
+
+dnl Checks for availability of GCC's atomic operations builtins.
+dnl Defines HAVE_GCC_ATOMIC_BUILTINS if available.
+
+AC_DEFUN([WX_ATOMIC_BUILTINS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  if test -n "$GCC"; then
+    AC_MSG_CHECKING([for __sync_fetch_* builtins])
+    AC_CACHE_VAL(wx_cv_cc_gcc_atomic_builtins, [
+      AC_TRY_COMPILE(
+        [],
+        [
+          int value=0;
+          __sync_fetch_and_add(&value, 1);
+          __sync_sub_and_fetch(&value, 1);
+        ],
+        wx_cv_cc_gcc_atomic_builtins=yes,
+        wx_cv_cc_gcc_atomic_builtins=no)
+      ])
+    AC_MSG_RESULT([$wx_cv_cc_gcc_atomic_builtins])
+    if test $wx_cv_cc_gcc_atomic_builtins = yes; then
+      AC_DEFINE([HAVE_GCC_ATOMIC_BUILTINS])
+    fi
+  fi
+])