require SQLite >= 3.21.0

After some testing it turns out we need at least SQLite 3.21.0 to
compile.

We _could_ work around this and make zig-sqlite work with older SQLite
versions but I don't think it's necessary because:
* "old" distributions like Debian Buster, RHEL 8 ship with SQLite >
  3.21.0
* in any case if people want to build for OSes where SQLite is too old
  they can use the bundled source code.

1 files changed, 11 insertions, 0 deletions

diff --git a/c.zig b/c.zig
index a346a3a..c15b987 100644
--- a/c.zig
+++ b/c.zig
@@ -1,3 +1,14 @@
 pub const c = @cImport({
     @cInclude("sqlite3.h");
 });
+
+// versionGreaterThanOrEqualTo returns true if the SQLite version is >= to the major.minor.patch provided.
+pub fn versionGreaterThanOrEqualTo(major: u8, minor: u8, patch: u8) bool {
+    return c.SQLITE_VERSION_NUMBER >= @as(u32, major) * 1000000 + @as(u32, minor) * 1000 + @as(u32, patch);
+}
+
+comptime {
+    if (!versionGreaterThanOrEqualTo(3, 21, 0)) {
+        @compileError("must use SQLite >= 3.21.0");
+    }
+}