libv4l: add patch to fix libjpeg build issue

From d468d1bba973999f2f1103ebaf7df5c8440a5499 Mon Sep 17 00:00:00 2001

From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Date: Thu, 21 Jan 2016 10:22:16 +0100

Subject: [PATCH] libv4lconvert: only expose jpeg_mem_*() protoypes when

 JPEG_LIB_VERSION < 80

The jpeg_memsrcdest.c file implements jpeg_mem_src() and

jpeg_mem_dest() when JPEG_LIB_VERSION < 80 in order to provide those

functions to libv4lconvert when the libjpeg library being used is too

old.

However, the jpeg_memsrcdest.h file exposes the prototypes of those

functions unconditionally. Until now, the prototype was matching the

one of the functions exposed by libjpeg (when JPEG_LIB_VERSION >= 80),

so there was no problem.

But since the release of libjpeg 9b (in January 2016), they changed

the second argument of jpeg_mem_src() from "unsigned char *" to "const

unsigned char*". Therefore, there are two prototypes for the

jpeg_mem_src() function: one from libjpeg, one from libv4l, and they

conflict with each other.

To resolve this situation, this patch modifies jpeg_memsrcdest.h to

only expose the prototypes when libv4l is implementing the functions

(i.e when JPEG_LIB_VERSION < 80). When JPEG_LIB_VERSION >= 80, the

prototypes will come from <jpeglib.h>.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

---

 lib/libv4lconvert/jpeg_memsrcdest.h | 4 ++++

 1 file changed, 4 insertions(+)

diff --git a/lib/libv4lconvert/jpeg_memsrcdest.h b/lib/libv4lconvert/jpeg_memsrcdest.h

index e971182..28a6477 100644

--- a/lib/libv4lconvert/jpeg_memsrcdest.h

+++ b/lib/libv4lconvert/jpeg_memsrcdest.h

@@ -1,5 +1,7 @@

 #include <jpeglib.h>

+#if JPEG_LIB_VERSION < 80

+

 void

 jpeg_mem_src (j_decompress_ptr cinfo, unsigned char * buffer,

 	unsigned long bufsize);

@@ -7,3 +9,5 @@ jpeg_mem_src (j_decompress_ptr cinfo, unsigned char * buffer,

 void

 jpeg_mem_dest (j_compress_ptr cinfo, unsigned char ** outbuffer,

 	unsigned long * outsize);

+

+#endif

-- 

2.6.4