jpeg_memsrcdest: extend feature check

libjpeg.h in OpenEmbedded master (from libjpeg-turbo 1.5.0) provides
these methods if "JPEG_LIB_VERSION >= 80 ||
defined(MEM_SRCDST_SUPPORTED)".

The support for the jpeg_mem functions was added even when not
emulating the libjpeg8 API, controlled via the MEM_SRCDST_SUPPORTED
define, so checking for the version alone is not enough anymore.

See libjpeg-turbo/libjpeg-turbo@ab70623

This fixes errors about conflicting declarations (signed vs. unsigned
char).

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>

camlibs/ax203/jpeg_memsrcdest.c

@@ -25,8 +25,8 @@
 #include "jpeg_memsrcdest.h"
 
 /* libjpeg8 and later come with their own (API compatible) memory source
-   and dest */
-#if JPEG_LIB_VERSION < 80
+   and dest, and older versions may have it backported */
+#if JPEG_LIB_VERSION < 80 && !defined(MEM_SRCDST_SUPPORTED)
 
 /* Expanded data source object for memory input */
 

camlibs/ax203/jpeg_memsrcdest.h

@@ -1,9 +1,13 @@
 #include <jpeglib.h>
 
+#if JPEG_LIB_VERSION < 80 && !defined(MEM_SRCDST_SUPPORTED)
+
 void
 jpeg_mem_src (j_decompress_ptr cinfo, unsigned char * buffer,
 	unsigned long bufsize);
 
 void
 jpeg_mem_dest (j_compress_ptr cinfo, unsigned char ** outbuffer,
 	unsigned long * outsize);
+
+#endif

camlibs/jl2005c/jpeg_memsrcdest.c

@@ -25,8 +25,8 @@
 #include "jpeg_memsrcdest.h"
 
 /* libjpeg8 and later come with their own (API compatible) memory source
-   and dest */
-#if JPEG_LIB_VERSION < 80
+   and dest, and older versions may have it backported */
+#if JPEG_LIB_VERSION < 80 && !defined(MEM_SRCDST_SUPPORTED)
 
 /* Expanded data source object for memory input */
 

camlibs/jl2005c/jpeg_memsrcdest.h

@@ -1,9 +1,13 @@
 #include <jpeglib.h>
 
+#if JPEG_LIB_VERSION < 80 && !defined(MEM_SRCDST_SUPPORTED)
+
 void
 jpeg_mem_src (j_decompress_ptr cinfo, unsigned char * buffer,
 	unsigned long bufsize);
 
 void
 jpeg_mem_dest (j_compress_ptr cinfo, unsigned char ** outbuffer,
 	unsigned long * outsize);
+
+#endif