Move OS-specific fopen quirks to o_fopen.c.

Reviewed-by: Richard Levitte <levitte@openssl.org>
diff --git a/crypto/build.info b/crypto/build.info
index 1b4ed14..916d24f 100644
--- a/crypto/build.info
+++ b/crypto/build.info
@@ -2,7 +2,7 @@
 LIBS=../libcrypto
 SOURCE[../libcrypto]=\
         cryptlib.c mem.c mem_dbg.c cversion.c ex_data.c cpt_err.c \
-        ebcdic.c uid.c o_time.c o_str.c o_dir.c \
+        ebcdic.c uid.c o_time.c o_str.c o_dir.c o_fopen.c \
         threads_pthread.c threads_win.c threads_none.c \
         o_init.c o_fips.c mem_sec.c init.c {- $target{cpuid_asm_src} -} \
         {- $target{uplink_aux_src} -}