Detect libdeflate >= 1.9 and adjust CRAM RN encoding.

Previously for read names compression levels between 4 and 7 zlib
considerably beat libdeflate due to libdeflate's poor selection of
minimum match length. This was raised as issue ebiggers/libdeflate#85.
It's now been resolved in libdeflate 1.9 (along with some general
improvements elsewhere), and in all cases libdeflate is a better
choice.

Also fixed the mapping of levels 1..9 (standard zlib) to 1..12
(libdeflate).  The maths in the comment was incorrect as it's an
integer calculation not a floating point one.

Figures from converting 1 million NovaSeq records from BAM to CRAM 3.0:

Libdeflate 1.9+PR-7  0m43.816s  204732408   48381374 (RN=libdeflate)
Libdeflate 1.8-7     0m45.379s  206626451   50580708 (RN=zlib)
Libdeflate 1.8-7     1m1.431s	210172035  *54126292 (RN=libdeflate, forced)
Zlib only -7         0m48.531s  207189920   50580708 (RN=zlib)

(Default level)
Libdeflate 1.9+PR-5  0m30.323s  207793059   51023626 (RN=libdeflate)
Libdeflate 1.8-5     0m33.265s  208714328   51612215 (RN=zlib, as devel)
Libdeflate 1.8-5     0m29.753s	213024792  *55922679 (RN=libdeflate, forced)
Zlib only -5         0m40.353s  208499406   51612215 (RN=zlib)

We can clearly see the problem(*) in using libdeflate for read-names in
1.8, how it's fixed in 1.9, and how it is now smaller/faster than zlib
again.

At level 9 it was using libdeflate for RN already, but we see
improvements to both RN and elsewhere which are simply down to other
changes in the library:

                     Time       Size        RN
Libdeflate 1.9+PR-9  2m21.757s  202890458   47327597 (RN=libdeflate)
Libdeflate 1.8-9     2m6.304s   204292448   48541687 (RN=libdeflate)
Zlib only -9         1m20.966s  206482425   49988310 (RN=zlib)

Finally, the impact of switching level 9 from the old mapping (11) to
new (12; "9+"), along with a more complete table for curiosities sake:

                     Time       Size        RN
Libdeflate 1.9+PR-9+ 2m54.664s  202315823   46783148
Libdeflate 1.9+PR-9  2m21.757s  202890458   47327597
Libdeflate 1.9+PR-8  1m39.040s  202934405   47247996
Libdeflate 1.9+PR-7  0m43.816s  204732408   48381374
Libdeflate 1.9+PR-6  0m31.521s  207437149   50768595
Libdeflate 1.9+PR-5  0m30.323s  207793059   51023626 (default level)
Libdeflate 1.9+PR-4  0m29.478s  210425588   52946850
Libdeflate 1.9+PR-1  0m27.460s  215975209   57142706 (no change)

(Note: "1.9" here is actually master, which is a few commits on from
the tag, but the main gist of it is the same.)

Author: jkbonfield

cram/cram_io.c

@@ -1108,8 +1108,8 @@ char *zlib_mem_inflate(char *cdata, size_t csize, size_t *size) {
 static char *libdeflate_deflate(char *data, size_t size, size_t *cdata_size,
                                 int level, int strat) {
     level = level > 0 ? level : 6; // libdeflate doesn't honour -1 as default
-    level *= 1.2; // NB levels go up to 12 here; 5 onwards is +1
-    if (level >= 8) level += level/8; // 8->10, 9->12
+    level *= 1.23;     // NB levels go up to 12 here; 5 onwards is +1
+    level += level>=8; // 5,6,7->6,7,8  8->10  9->12
     if (level > 12) level = 12;
 
     if (strat == Z_RLE) // not supported by libdeflate
@@ -1213,6 +1213,7 @@ char *zlib_mem_inflate(char *cdata, size_t csize, size_t *size) {
 }
 #endif
 
+#if !defined(HAVE_LIBDEFLATE) || LIBDEFLATE_VERSION_MAJOR < 1 || (LIBDEFLATE_VERSION_MAJOR ==  1 && LIBDEFLATE_VERSION_MINOR <= 8)
 static char *zlib_mem_deflate(char *data, size_t size, size_t *cdata_size,
                               int level, int strat) {
     z_stream s;
@@ -1269,6 +1270,7 @@ static char *zlib_mem_deflate(char *data, size_t size, size_t *cdata_size,
     }
     return (char *)cdata;
 }
+#endif
 
 #ifdef HAVE_LIBLZMA
 /* ------------------------------------------------------------------------ */
@@ -1754,9 +1756,11 @@ static char *cram_compress_by_method(cram_slice *s, char *in, size_t in_size,
         //
         // Eg RN at level 5;  libdeflate=55.9MB  zlib=51.6MB
 #ifdef HAVE_LIBDEFLATE
+#  if (LIBDEFLATE_VERSION_MAJOR < 1 || (LIBDEFLATE_VERSION_MAJOR == 1 && LIBDEFLATE_VERSION_MINOR <= 8))
         if (content_id == DS_RN && level >= 4 && level <= 7)
             return zlib_mem_deflate(in, in_size, out_size, level, strat);
         else
+#  endif
             return libdeflate_deflate(in, in_size, out_size, level, strat);
 #else
         return zlib_mem_deflate(in, in_size, out_size, level, strat);