Initial pass on SQLite C ABI

This adds initial SQLite C ABI compatibility to Limbo to make sure we
drive the Rust API in the right way that allows us to implement SQLite
semantics.

sqlite3/tests/.gitignore

@@ -0,0 +1,3 @@
+sqlite3-tests
+*.d
+*.o

sqlite3/tests/Makefile

@@ -0,0 +1,38 @@
+V =
+ifeq ($(strip $(V)),)
+	E = @echo
+	Q = @
+else
+	E = @\#
+	Q =
+endif
+export E Q
+
+PROGRAM = sqlite3-tests
+
+CFLAGS = -g -Wall -std=c17 -MMD -MP
+
+LIBS ?= -lsqlite3
+
+OBJS += main.o
+OBJS += test-close.o
+OBJS += test-open.o
+OBJS += test-prepare.o
+
+all: $(PROGRAM)
+
+%.o: %.c
+	$(E) "  CC      " $@
+	$(Q) $(CC) $(CFLAGS) -c $< -o $@
+
+$(PROGRAM): $(OBJS)
+	$(E) "  LINK    " $@
+	$(Q) $(CC) $(LIBS) -o $@ $^
+
+clean:
+	$(E) "  CLEAN"
+	$(Q) rm -f $(PROGRAM)
+	$(Q) rm -f $(OBJS) *.d
+.PHONY: clean
+
+-include $(OBJS:.o=.d)

sqlite3/tests/check.h

@@ -0,0 +1,11 @@
+#ifndef CHECK_H
+
+#define CHECK_EQUAL(expected, actual) \
+	do { \
+		if ((expected) != (actual)) { \
+			fprintf(stderr, "%s:%d: Assertion failed: %d != %d\n", __FILE__, __LINE__, (expected), (actual)); \
+			exit(1); \
+		} \
+	} while (0)
+
+#endif

sqlite3/tests/main.c

@@ -0,0 +1,16 @@
+extern void test_open_misuse();
+extern void test_open_not_found();
+extern void test_open_existing();
+extern void test_close();
+extern void test_prepare_misuse();
+
+int main(int argc, char *argv[])
+{
+	test_open_misuse();
+	test_open_not_found();
+	test_open_existing();
+	test_close();
+	test_prepare_misuse();
+
+	return 0;
+}

sqlite3/tests/test-close.c

@@ -0,0 +1,11 @@
+#include <sqlite3.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "check.h"
+
+void test_close(void)
+{
+	CHECK_EQUAL(SQLITE_OK, sqlite3_close(NULL));
+}

sqlite3/tests/test-open.c

@@ -0,0 +1,30 @@
+#include "check.h"
+
+#include <sqlite3.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+void test_open_misuse(void)
+{
+	CHECK_EQUAL(SQLITE_MISUSE, sqlite3_open(NULL, NULL));
+
+	CHECK_EQUAL(SQLITE_MISUSE, sqlite3_open("local.db", NULL));
+}
+
+void test_open_not_found(void)
+{
+	sqlite3 *db;
+
+	CHECK_EQUAL(SQLITE_CANTOPEN, sqlite3_open("not-found/local.db", &db));
+}
+
+// TODO: test_open_create
+
+void test_open_existing(void)
+{
+	sqlite3 *db;
+
+	CHECK_EQUAL(SQLITE_OK, sqlite3_open("../../testing/hello.db", &db));
+	CHECK_EQUAL(SQLITE_OK, sqlite3_close(db));
+}