Correctly implemented multithreaded tests. (#15)

* Correctly implemented multithreaded tests.
  * I had first attempted this in #2, but removed because my implementation was flawed.
  * This implementation should do everything correctly.
* Updated ignores to be directory-relative.
* macOS: use GCC instead of Apple C compiler.
  * Because the default compiler does not support standard threads, and does not set the macro indicating the same.
  * Neither does any version of GCC.
* Disabled multithreading in macOS tests.
* Switched back to default C compiler on macOS.

.gitignore

@@ -1 +1,2 @@
-build
+/.vscode/
+/build

benchmarks/.gitignore

@@ -1,2 +1,2 @@
-benchmarks
-benchmarks.exe
+/benchmarks
+/benchmarks.exe

examples/C++/.gitignore

@@ -1,4 +1,4 @@
-thread-safe
-thread-safe.exe
-thread-unsafe
-thread-unsafe.exe
+/thread-safe
+/thread-safe.exe
+/thread-unsafe
+/thread-unsafe.exe

examples/C/.gitignore

@@ -1,4 +1,4 @@
-thread-safe
-thread-safe.exe
-thread-unsafe
-thread-unsafe.exe
+/thread-safe
+/thread-safe.exe
+/thread-unsafe
+/thread-unsafe.exe

lib/.gitignore

@@ -1,4 +1,4 @@
-hdrbg.egg-info
-*.dll
-*.o
-*.so
+/hdrbg.egg-info/
+/*.dll
+/*.o
+/*.so

tests/.gitignore

@@ -1,2 +1,2 @@
-tests
-tests.exe
+/tests
+/tests.exe

tests/tests.c

@@ -4,7 +4,15 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdio.h>
-#include <stdlib.h>
+
+// The C compilers available on the macOS runners on GitHub Actions do not
+// indicate their lack of support for standard threads with the expected
+// preprocessor macro, so disable multithreading on macOS.
+#if defined __APPLE__ || defined __STDC_NO_THREADS__
+#define STDC_NO_THREADS
+#else
+#include <threads.h>
+#endif
 
 #define WORKERS_SIZE 8
 #define CUSTOM_ITERATIONS (1L << 16)
@@ -56,19 +64,6 @@ hdrbg_tests_custom(void *hd_)
     return 0;
 }
 
-/******************************************************************************
- * Test a particular HDRBG object.
- *
- * @param hd HDRBG object.
- * @param tv Test vectors file.
- *****************************************************************************/
-void
-tests(struct hdrbg_t *hd, FILE *tv)
-{
-    hdrbg_tests(hd, tv);
-    hdrbg_tests_custom(hd);
-}
-
 /******************************************************************************
  * Main function.
  *****************************************************************************/
@@ -77,14 +72,37 @@ main(void)
 {
     printf("Testing a dynamically-allocated HDRBG object.\n");
     FILE *tv = fopen("Hash_DRBG.dat", "rb");
-    struct hdrbg_t *hd = hdrbg_init(true);
-    tests(hd, tv);
-    hdrbg_zero(hd);
+    struct hdrbg_t *hds[WORKERS_SIZE];
+    for (int i = 0; i < WORKERS_SIZE; ++i)
+    {
+        hds[i] = hdrbg_init(true);
+        hdrbg_tests(hds[i], tv);
+        rewind(tv);
+    }
+#ifndef STDC_NO_THREADS
+    thrd_t workers[WORKERS_SIZE];
+#endif
+    for (int i = 0; i < WORKERS_SIZE; ++i)
+    {
+#ifndef STDC_NO_THREADS
+        thrd_create(workers + i, hdrbg_tests_custom, hds[i]);
+#else
+        hdrbg_tests_custom(hds[i]);
+#endif
+    }
+    for (int i = 0; i < WORKERS_SIZE; ++i)
+    {
+#ifndef STDC_NO_THREADS
+        thrd_join(workers[i], NULL);
+#endif
+        hdrbg_zero(hds[i]);
+    }
     printf("All tests passed.\n");
 
     printf("Testing the internal HDRBG object.\n");
     rewind(tv);
-    tests(NULL, tv);
+    hdrbg_tests(NULL, tv);
+    hdrbg_tests_custom(NULL);
     fclose(tv);
     printf("All tests passed.\n");
 }