Add sqlite extension for generating uuid's.

Makefile

+libs = sqlite3 uuid
+CFLAGS = -Wall -pedantic -std=c2x -fPIC \
+		 -ggdb \
+		 $(shell pkg-config --cflags $(libs))
+LDLIBS = $(shell pkg-config --libs $(libs))
+
+C_FILES = sqlite-uuid.c
+O_FILES = $(C_FILES:%.c=%.o)
+
+sqlite-uuid.so: $(O_FILES)
+	$(CC) -shared -o $@ $^ $(LDLIBS)

sqlite-uuid.c

+#include <sqlite3ext.h>
+SQLITE_EXTENSION_INIT1
+#include <uuid.h>
+
+static void sqlite_uuid(sqlite3_context *context, int argc, sqlite3_value **argv) {
+	uuid_t uuid;
+	uuid_generate_random(uuid);
+
+	char str[37];
+	uuid_unparse(uuid, &str[0]);
+
+	sqlite3_result_text(context, str, 37, SQLITE_TRANSIENT);
+
+	uuid_clear(uuid);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_extension_init (
+	sqlite3 *db,
+	char **pzErrMsg,
+	const sqlite3_api_routines *pApi
+) {
+	int rc = SQLITE_OK;
+	SQLITE_EXTENSION_INIT2(pApi);
+
+	(void) pzErrMsg;
+
+	rc = sqlite3_create_function(db, "uuid", 0,
+	   SQLITE_UTF8|SQLITE_INNOCUOUS,
+	   0, sqlite_uuid, 0, 0);
+
+	return rc;
+}

test.sql

+.load sqlite-uuid
+SELECT uuid();