add an inline hint where i expect inlining

i expected that modern compilers simply ignore inline specifiers
as compilers tend to be smarter than average programmers like me
these days. but it seems at least llvm still honors it. and at least
for this instance, adding the specifier produces considerably
faster code for my environment.

lib/leb128.c

@@ -22,7 +22,7 @@ read_u8(const uint8_t **pp, const uint8_t *ep, uint8_t *resultp)
         return 0;
 }
 
-static int
+static inline int
 read_leb(const uint8_t **pp, const uint8_t *ep, unsigned int bits,
          bool is_signed, uint64_t *resultp)
 {