Fix inline functions when compiling as C99.

Make private inlines in C files 'static inline', not just 'inline', or the compiler
can discard the definition if it chooses not to inline it.

Make functions declared in header files not be declared inline (if they're defined in a
.c file).  It looks like no functions in this category are used in LibSRTP's critical
path, only for unit tests or generating AES tables.

To see the problem prior to this commit, compile with "gcc -O0 -std=gnu99".
Signed-off-by: Travis Cross <tc@traviscross.com>

This cherry-picks commit e2774dbd551ffe5f872eaec2b2d40b712a54e1ba from
libsrtp upstream.

FS-6196 --resolve

libs/srtp/crypto/cipher/aes_icm.c

@@ -284,7 +284,7 @@ aes_icm_set_iv(aes_icm_ctx_t *c, void *iv) {
  * this is an internal, hopefully inlined function
  */
   
-inline void
+static inline void
 aes_icm_advance_ismacryp(aes_icm_ctx_t *c, uint8_t forIsmacryp) {
   /* fill buffer with new keystream */
   v128_copy(&c->keystream_buffer, &c->counter);
@@ -309,7 +309,7 @@ aes_icm_advance_ismacryp(aes_icm_ctx_t *c, uint8_t forIsmacryp) {
   }
 }
 
-inline void aes_icm_advance(aes_icm_ctx_t *c) {
+static inline void aes_icm_advance(aes_icm_ctx_t *c) {
   aes_icm_advance_ismacryp(c, 0);
 }
 

libs/srtp/crypto/math/datatypes.c

@@ -124,7 +124,7 @@ octet_string_hex_string(const void *s, int length) {
   return bit_string;
 }
 
-inline int
+static inline int
 hex_char_to_nibble(uint8_t c) {
   switch(c) {
   case ('0'): return 0x0;

libs/srtp/crypto/math/gf2_8.c

@@ -50,7 +50,7 @@
 
 /* gf2_8_shift() moved to gf2_8.h as an inline function */
 
-inline gf2_8
+gf2_8
 gf2_8_multiply(gf2_8 x, gf2_8 y) {
   gf2_8 z = 0;
 

libs/srtp/crypto/math/math.c

@@ -173,7 +173,7 @@ v32_weight(v32_t a) {
   return wt;
 }
 
-inline unsigned char
+unsigned char
 v32_distance(v32_t x, v32_t y) {
   x.value ^= y.value;
   return v32_weight(x);
@@ -524,13 +524,13 @@ A_times_x_plus_b(uint8_t A[8], uint8_t x, uint8_t b) {
   return b;
 }
 
-inline void
+void
 v16_copy_octet_string(v16_t *x, const uint8_t s[2]) {
   x->v8[0]  = s[0];
   x->v8[1]  = s[1];
 }
 
-inline void
+void
 v32_copy_octet_string(v32_t *x, const uint8_t s[4]) {
   x->v8[0]  = s[0];
   x->v8[1]  = s[1];
@@ -538,7 +538,7 @@ v32_copy_octet_string(v32_t *x, const uint8_t s[4]) {
   x->v8[3]  = s[3];
 }
 
-inline void
+void
 v64_copy_octet_string(v64_t *x, const uint8_t s[8]) {
   x->v8[0]  = s[0];
   x->v8[1]  = s[1];
@@ -632,7 +632,7 @@ v128_set_bit_to(v128_t *x, int i, int y){
 #endif /* DATATYPES_USE_MACROS */
 
 
-inline void
+static inline void
 v128_left_shift2(v128_t *x, int num_bits) {
   int i;
   int word_shift = num_bits >> 5;