Improve FindWrapRt, and SHM detection

Apparently, more and more librt functionality are being moved to glibc
these days, e.g., clock_gettime, clock_getres, clock_settime,
clock_getcpuclockid, clock_nanosleep. As Thiago mentioned, in face,
all librt functions are moving into glibc, but unlike the clock_*
functions that I can see are ported from 2.17+, I cannot find out when
and what functions are already ported. So, here, I added a second test
which tries to explicitly look for shm_* functions, if they are there,
as well as the clock_* function, then we are more confident that we
actually have a useful the libRt in the system.

Also, making the FEATURE_posix_SHM depends on UNIX.

Pick-to: 6.5
Fixes: QTBUG-111049
Change-Id: I08b7f4656ecd9313b552fb05ca7096f5b987b95a
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

cmake/FindWrapRt.cmake

@@ -21,17 +21,31 @@ if(LIBRT)
 endif()
 
 check_cxx_source_compiles("
-#include <unistd.h>
 #include <time.h>
+#include <unistd.h>
 
 int main(int, char **) {
-    timespec ts; clock_gettime(CLOCK_REALTIME, &ts);
+    struct timespec ts;
-}" HAVE_GETTIME)
+    clock_gettime(CLOCK_REALTIME, &ts);
+    return 0;
+}
+" HAVE_GETTIME)
+
+check_cxx_source_compiles("
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+
+int main(int, char **) {
+    shm_open(\"test\", O_RDWR | O_CREAT | O_EXCL, 0666);
+    shm_unlink(\"test\");
+    return 0;
+}
+" HAVE_SHM_OPEN_SHM_UNLINK)
 
 cmake_pop_check_state()
 
-
+if(HAVE_GETTIME OR HAVE_SHM_OPEN_SHM_UNLINK)
-if(HAVE_GETTIME)
     set(WrapRt_FOUND ON)
     add_library(WrapRt::WrapRt INTERFACE IMPORTED)
     if (LIBRT)

src/corelib/CMakeLists.txt

@@ -1140,14 +1140,16 @@ qt_internal_extend_target(Core CONDITION QT_FEATURE_glib AND UNIX
         GLIB2::GLIB2
 )
 
-qt_internal_extend_target(Core CONDITION QT_FEATURE_clock_gettime AND UNIX
+qt_internal_extend_target(Core CONDITION QT_FEATURE_clock_gettime
     LIBRARIES
         WrapRt::WrapRt
 )
 
-qt_internal_extend_target(Core CONDITION QT_FEATURE_posix_shm
+qt_internal_extend_target(Core CONDITION QT_FEATURE_posix_shm AND UNIX
     SOURCES
         ipc/qsharedmemory_posix.cpp
+    LIBRARIES
+        WrapRt::WrapRt
 )
 qt_internal_extend_target(Core CONDITION QT_FEATURE_sysv_shm
     SOURCES
@@ -1156,6 +1158,8 @@ qt_internal_extend_target(Core CONDITION QT_FEATURE_sysv_shm
 qt_internal_extend_target(Core CONDITION QT_FEATURE_posix_sem
     SOURCES
         ipc/qsystemsemaphore_posix.cpp
+    LIBRARIES
+        WrapRt::WrapRt
 )
 qt_internal_extend_target(Core CONDITION QT_FEATURE_sysv_sem
     SOURCES

src/corelib/configure.cmake

@@ -331,7 +331,7 @@ int main(void)
 ")
 
 if (LINUX)
-    set(ipc_posix_TEST_LIBRARIES pthread rt)
+    set(ipc_posix_TEST_LIBRARIES pthread WrapRt::WrapRt)
 endif()
 qt_config_compile_test(posix_shm
     LABEL "POSIX shared memory"
@@ -692,7 +692,7 @@ qt_feature("posix_sem" PRIVATE
 )
 qt_feature("posix_shm" PRIVATE
     LABEL "POSIX shared memory"
-    CONDITION TEST_posix_shm
+    CONDITION TEST_posix_shm AND UNIX
 )
 qt_feature("qqnx_pps" PRIVATE
     LABEL "PPS"