Test threads with both C and C++.

test cases/common/102 threads/meson.build

@@ -1,7 +1,15 @@
-project('threads', 'cpp')
+project('threads', 'cpp', 'c')
 
-test('threadtest',
-  executable('threadprog', 'threadprog.cpp',
-    dependencies : dependency('threads')
+threaddep = dependency('threads')
+
+test('cppthreadtest',
+  executable('cppthreadprog', 'threadprog.cpp',
+    dependencies : threaddep
+  )
+)
+
+test('cthreadtest',
+  executable('cthreadprog', 'threadprog.c',
+    dependencies : threaddep
   )
 )

test cases/common/102 threads/threadprog.c

@@ -0,0 +1,40 @@
+#if defined _WIN32
+
+#include<windows.h>
+#include<stdio.h>
+
+DWORD WINAPI thread_func(LPVOID ignored) {
+    printf("Printing from a thread.\n");
+    return 0;
+}
+
+int main(int argc, char **argv) {
+    printf("Starting thread.\n");
+    HANDLE th;
+    DWORD id;
+    th = CreateThread(NULL, 0, thread_func, NULL, 0, &id);
+    WaitForSingleObject(th, INFINITE);
+    printf("Stopped thread.\n");
+    return 0;
+}
+#else
+
+#include<pthread.h>
+#include<stdio.h>
+
+void* main_func(void* ignored) {
+    printf("Printing from a thread.\n");
+    return NULL;
+}
+
+int main(int argc, char** argv) {
+    pthread_t thread;
+    int rc;
+    printf("Starting thread.\n");
+    rc = pthread_create(&thread, NULL, main_func, NULL);
+    rc = pthread_join(thread, NULL);
+    printf("Stopped thread.\n");
+    return rc;
+}
+
+#endif