[PATCH/RFC 3/7] imap-send: fix compilation-error on Windows

mmsystem.h (included from windows.h) defines DRV_OK to 1. To avoid
an error due to DRV_OK redefenition, this patch undefines the old
definition (i.e the one from mmsystem.h) before defining DRV_OK.

Signed-off-by: Erik Faye-Lund <redacted>
---
 imap-send.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/imap-send.c b/imap-send.c
index 55a663a..8338717 100644
--- a/imap-send.c
+++ b/imap-send.c

@@ -94,6 +94,10 @@ struct msg_data {
 	unsigned int crlf:1;
 };
 
+#ifdef DRV_OK
+#undef DRV_OK
+#endif
+
 #define DRV_OK          0
 #define DRV_MSG_BAD     -1
 #define DRV_BOX_BAD     -2

-- 
1.6.5.rc2.7.g4f8d3