fixed linking error for newer compilers

algorithm/fresh.c

@@ -49,7 +49,7 @@ typedef struct {
   sph_echo512_context     echo2;
 } FreshHash_context_holder;
 
-FreshHash_context_holder base_contexts;
+static FreshHash_context_holder base_contexts;
 
 void init_freshHash_contexts()
 {

algorithm/qubitcoin.c

@@ -50,7 +50,7 @@ typedef struct {
     sph_echo512_context     echo1;
 } Qhash_context_holder;
 
-Qhash_context_holder base_contexts;
+static Qhash_context_holder base_contexts;
 
 
 void init_Qhash_contexts()

algorithm/whirlcoin.c

@@ -44,7 +44,7 @@ typedef struct {
   sph_whirlpool1_context whirlpool4;
 } Whash_context_holder;
 
-Whash_context_holder base_contexts;
+static Whash_context_holder base_contexts;
 
 
 void init_whirlcoin_hash_contexts()

miner.h

@@ -246,7 +246,7 @@ enum drv_driver {
 
 /* Use DRIVER_PARSE_COMMANDS to generate extern device_drv prototypes */
 #ifndef _MSC_VER
-DRIVER_PARSE_COMMANDS(DRIVER_PROTOTYPE)
+extern DRIVER_PARSE_COMMANDS(DRIVER_PROTOTYPE)
 #endif
 
 // helper to check for empty or NULL strings