CLEANUP: ncbuf: inline small functions

ncbuf API relies on lot of small functions. Mark these functions as
inline to reduce call invocations and facilitate compiler optimizations
to reduce code size.

This should be backported up to 2.6.
diff --git a/src/ncbuf.c b/src/ncbuf.c
index dab9196..5b661f4 100644
--- a/src/ncbuf.c
+++ b/src/ncbuf.c
@@ -28,6 +28,8 @@
 # define BUG_ON_HOT(x) if (x) { fprintf(stderr, "CRASH ON %s:%d\n", __func__, __LINE__); abort(); }
 #endif /* DEBUG_DEV */
 
+#include <haproxy/compiler.h>
+
 /* ******** internal API ******** */
 
 #define NCB_BLK_NULL ((struct ncb_blk){ .st = NULL })
@@ -64,7 +66,7 @@
 }
 
 /* Encode <off> at <st> position in <buf>. Support wrapping. */
-static void ncb_write_off(const struct ncbuf *buf, char *st, ncb_sz_t off)
+static forceinline void ncb_write_off(const struct ncbuf *buf, char *st, ncb_sz_t off)
 {
 	int i;
 
@@ -79,7 +81,7 @@
 }
 
 /* Decode offset stored at <st> position in <buf>. Support wrapping. */
-static ncb_sz_t ncb_read_off(const struct ncbuf *buf, char *st)
+static forceinline ncb_sz_t ncb_read_off(const struct ncbuf *buf, char *st)
 {
 	int i;
 	ncb_sz_t off = 0;
@@ -97,26 +99,26 @@
 }
 
 /* Add <off> to the offset stored at <st> in <buf>. Support wrapping. */
-static void ncb_inc_off(const struct ncbuf *buf, char *st, ncb_sz_t off)
+static forceinline void ncb_inc_off(const struct ncbuf *buf, char *st, ncb_sz_t off)
 {
 	const ncb_sz_t old = ncb_read_off(buf, st);
 	ncb_write_off(buf, st, old + off);
 }
 
 /* Returns true if a gap cannot be inserted at <off> : a reduced gap must be used. */
-static int ncb_off_reduced(const struct ncbuf *b, ncb_sz_t off)
+static forceinline int ncb_off_reduced(const struct ncbuf *b, ncb_sz_t off)
 {
 	return off + NCB_GAP_MIN_SZ > ncb_size(b);
 }
 
 /* Returns true if <blk> is the special NULL block. */
-static int ncb_blk_is_null(const struct ncb_blk *blk)
+static forceinline int ncb_blk_is_null(const struct ncb_blk *blk)
 {
 	return !blk->st;
 }
 
 /* Returns true if <blk> is the last block of <buf>. */
-static int ncb_blk_is_last(const struct ncbuf *buf, const struct ncb_blk *blk)
+static forceinline int ncb_blk_is_last(const struct ncbuf *buf, const struct ncb_blk *blk)
 {
 	BUG_ON_HOT(blk->off + blk->sz > ncb_size(buf));
 	return blk->off + blk->sz == ncb_size(buf);
@@ -214,7 +216,7 @@
 }
 
 /* Transform absolute offset <off> to a relative one from <blk> start. */
-static ncb_sz_t ncb_blk_off(const struct ncb_blk *blk, ncb_sz_t off)
+static forceinline ncb_sz_t ncb_blk_off(const struct ncb_blk *blk, ncb_sz_t off)
 {
 	BUG_ON_HOT(off < blk->off || off > blk->off + blk->sz);
 	BUG_ON_HOT(off - blk->off > blk->sz);
@@ -375,11 +377,6 @@
 
 /* ******** public API ******** */
 
-int ncb_is_null(const struct ncbuf *buf)
-{
-	return buf->size == 0;
-}
-
 /* Initialize or reset <buf> by clearing all data. Its size is untouched.
  * Buffer is positioned to <head> offset. Use 0 to realign it. <buf> must not
  * be NCBUF_NULL.
@@ -413,35 +410,6 @@
 	return buf;
 }
 
-/* Returns start of allocated buffer area. */
-char *ncb_orig(const struct ncbuf *buf)
-{
-	return buf->area;
-}
-
-/* Returns current head pointer into buffer area. */
-char *ncb_head(const struct ncbuf *buf)
-{
-	return buf->area + buf->head;
-}
-
-/* Returns the first byte after the allocated buffer area. */
-char *ncb_wrap(const struct ncbuf *buf)
-{
-	return buf->area + buf->size;
-}
-
-/* Returns the usable size of <buf> for data storage. This is the size of the
- * allocated buffer without the reserved header space.
- */
-ncb_sz_t ncb_size(const struct ncbuf *buf)
-{
-	if (ncb_is_null(buf))
-		return 0;
-
-	return buf->size - NCB_RESERVED_SZ;
-}
-
 /* Returns the total number of bytes stored in whole <buf>. */
 ncb_sz_t ncb_total_data(const struct ncbuf *buf)
 {