base64: Migrate over to osmocom

This containts the osmocom changes to the mbedtls base64 code
merged in the previous commit.

Change-Id: I82c1bf5f827c8def370dbcb80b146e9e4184c4a3
diff --git a/src/Makefile.am b/src/Makefile.am
index 2f18d09..3c589e6 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -31,6 +31,7 @@
 			 exec.c \
 			 it_q.c \
 			 probes.d \
+			 base64.c \
 			 $(NULL)
 
 if HAVE_SSSE3