vsprintf.c: add GUID printing

This works (roughly) the same way as linux's, but we currently always
print lower-case (ie. we just keep %pUB and %pUL for compat with linux),
mostly just because that is what uuid_bin_to_str() supports.

  %pUb:   01020304-0506-0708-090a-0b0c0d0e0f10
  %pUl:   04030201-0605-0807-090a-0b0c0d0e0f10

It will be used by a later efi_loader paths for efi variables and for
device-path-to-text protocol, and also quite useful for debug prints
of protocol GUIDs.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/examples/api/Makefile b/examples/api/Makefile
index 87c15d0..8995272 100644
--- a/examples/api/Makefile
+++ b/examples/api/Makefile
@@ -35,6 +35,7 @@
 EXT_COBJ-y += lib/time.o
 EXT_COBJ-y += lib/vsprintf.o
 EXT_COBJ-y += lib/charset.o
+EXT_COBJ-$(CONFIG_LIB_UUID) += lib/uuid.o
 EXT_SOBJ-$(CONFIG_PPC) += arch/powerpc/lib/ppcstring.o
 ifeq ($(ARCH),arm)
 EXT_SOBJ-$(CONFIG_USE_ARCH_MEMSET) += arch/arm/lib/memset.o