The default main thread name is undefined, so use a constructor to
explicitly set it to 'main'. This constructor is marked to run early
as the thread name is intended to be used in error reporting / logs
which may be triggered very early in QEMU execution.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Dr. David Alan Gilbert <dave@treblig.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 util/qemu-thread-posix.c | 6 ++++++
 util/qemu-thread-win32.c | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
index ddaa1de4dd..275445ed94 100644
--- a/util/qemu-thread-posix.c
+++ b/util/qemu-thread-posix.c
@@ -22,6 +22,12 @@
 #include <pthread_np.h>
 #endif
 
+static void __attribute__((__constructor__(QEMU_CONSTRUCTOR_EARLY)))
+qemu_thread_init(void)
+{
+    qemu_thread_set_name("main");
+}
+
 static void error_exit(int err, const char *msg)
 {
     fprintf(stderr, "qemu: %s: %s\n", msg, strerror(err));
diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c
index 62eaa11026..7a734a7a09 100644
--- a/util/qemu-thread-win32.c
+++ b/util/qemu-thread-win32.c
@@ -22,6 +22,12 @@ typedef HRESULT (WINAPI *pSetThreadDescription) (HANDLE hThread,
 static pSetThreadDescription SetThreadDescriptionFunc;
 static HMODULE kernel32_module;
 
+static void __attribute__((__constructor__(QEMU_CONSTRUCTOR_EARLY)))
+qemu_thread_init(void)
+{
+    qemu_thread_set_name("main");
+}
+
 static bool load_set_thread_description(void)
 {
     static gsize _init_once = 0;
-- 
2.50.1