In hopes of un-breaking the buildfarm, add missing file from

ITAGAKI Takahiro's patch.

src/interfaces/ecpg/test/thread/alloc.pgc

+#include <stdlib.h>
+#include "ecpg_config.h"
+
+#ifndef ENABLE_THREAD_SAFETY
+int
+main(void)
+{
+	printf("No threading enabled.\n");
+	return 0;
+}
+#else
+#ifdef WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <process.h>
+#else
+#include <pthread.h>
+#endif
+#include <stdio.h>
+
+#define THREADS		16
+#define REPEATS		50
+
+exec sql include sqlca;
+exec sql include ../regression;
+
+exec sql whenever sqlerror sqlprint;
+exec sql whenever not found sqlprint;
+
+#ifdef WIN32
+static unsigned STDCALL fn(void* arg)
+#else
+static void* fn(void* arg)
+#endif
+{
+	int i;
+
+	EXEC SQL BEGIN DECLARE SECTION;
+	int  value;
+	char name[100];
+	char **r = NULL;
+	EXEC SQL END DECLARE SECTION;
+
+	value = (int)arg;
+	sprintf(name, "Connection: %d", value);
+
+	EXEC SQL CONNECT TO REGRESSDB1 AS :name;
+	EXEC SQL SET AUTOCOMMIT TO ON;
+	for (i = 1; i <= REPEATS; ++i)
+	{
+		EXEC SQL SELECT relname INTO :r FROM pg_class WHERE relname = 'pg_class';
+		free(r);
+		r = NULL;
+	}
+	EXEC SQL DISCONNECT :name;
+
+	return 0;
+}
+
+int main (int argc, char** argv)
+{
+	int i;
+#ifdef WIN32
+	HANDLE threads[THREADS];
+#else
+	pthread_t threads[THREADS];
+#endif
+
+#ifdef WIN32
+	for (i = 0; i < THREADS; ++i)
+	{
+		unsigned id;
+		threads[i] = (HANDLE)_beginthreadex(NULL, 0, fn, (void*)i, 0, &id);
+	}
+
+	WaitForMultipleObjects(THREADS, threads, TRUE, INFINITE);
+	for (i = 0; i < THREADS; ++i)
+		CloseHandle(threads[i]);
+#else
+	for (i = 0; i < THREADS; ++i)
+		pthread_create(&threads[i], NULL, fn, (void*)i);
+	for (i = 0; i < THREADS; ++i)
+		pthread_join(threads[i], NULL);
+#endif
+
+	return 0;
+}
+#endif
+