fixup bfdev: fixup some symbol export typo

src/log/log.c

@@ -56,7 +56,7 @@ log_get_level(const char *str)
     return 0;
 }
 
-extern unsigned int
+export unsigned int
 bfdev_log_level(const char *str, const char **endptr)
 {
     unsigned int level;

src/port/stdlib.c

@@ -7,7 +7,7 @@
 #include <port/stdlib.h>
 #include <export.h>
 
-extern __bfdev_noreturn void
+export __bfdev_noreturn void
 bfdev_abort(void)
 {
     bfport_abort();

src/port/string.c

@@ -7,67 +7,67 @@
 #include <port/string.h>
 #include <export.h>
 
-void *
+export void *
 bfdev_memcpy(void *dest, const void *src, bfdev_size_t n)
 {
     return bfport_memcpy(dest, src, n);
 }
 
-void *
+export void *
 bfdev_memset(void *s, int c, bfdev_size_t n)
 {
     return bfport_memset(s, c, n);
 }
 
-int
+export int
 bfdev_memcmp(const void *s1, const void *s2, bfdev_size_t n)
 {
     return bfport_memcmp(s1, s2, n);
 }
 
-int
+export int
 bfdev_strcmp(const char *s1, const char *s2)
 {
     return bfport_strcmp(s1, s2);
 }
 
-char *
+export char *
 bfdev_strchr(const char *s, int c)
 {
     return bfport_strchr(s, c);
 }
 
-bfdev_size_t
+export bfdev_size_t
 bfdev_strspn(const char *s, const char *accept)
 {
     return bfport_strspn(s, accept);
 }
 
-bfdev_size_t
+export bfdev_size_t
 bfdev_strcspn(const char *s, const char *reject)
 {
     return bfport_strcspn(s, reject);
 }
 
-char *
+export char *
 bfdev_strcpy(char *dest, const char *src)
 {
     return bfport_strcpy(dest, src);
 }
 
-char *
+export char *
 bfdev_strncpy(char *dest, const char *src, bfdev_size_t n)
 {
     return bfport_strncpy(dest, src, n);
 }
 
-bfdev_size_t
+export bfdev_size_t
 bfdev_strlen(const char *s)
 {
     return bfport_strlen(s);
 }
 
-bfdev_size_t
+export bfdev_size_t
 bfdev_strnlen(const char *s, bfdev_size_t len)
 {
     return bfport_strnlen(s, len);