alpine: use termux tmp dir for locks (#2127)

packages/alpine/env_unix.c.patch

@@ -0,0 +1,13 @@
+diff --git a/imap/src/osdep/unix/env_unix.c b/imap/src/osdep/unix/env_unix.c
+index 89e5092..f5a734e 100644
+--- a/imap/src/osdep/unix/env_unix.c
++++ b/imap/src/osdep/unix/env_unix.c
+@@ -123,7 +123,7 @@ static char *lockpgm = LOCKPGM;
+  * systems.
+  */
+ 
+-static const char *tmpdir = "/tmp";
++static const char *tmpdir = "@TERMUX_PREFIX@/tmp";
+ 
+ /* Do not change shlock_mode.  Doing so can cause mailbox corruption and
+  * denial of service.  It also defeats the entire purpose of the shared