[GRASS-dev] Notice about --with-ffmpeg and preC99 compilers

[Māris Nartišs]

Hi,

could somebody add a notice to INSTALL file that using --with-ffmpeg breaks 
build with preC99 compilers as ffmpeg include files use one line comments //, 
that where introduced with C99.

Tested on GNU/Linux x86
gcc version 4.1.2 20060920 (prerelease)
ffmpeg 3:0.cvs20060823

You can test it by yourself as described in doc/debuging.txt:
compile GRASS with 
CFLAGS='-g -ansi -Wall -D_BSD_SOURCE=1 -D_SVID_SOURCE=1 -D_POSIX_SOURCE=1 -D_POSIX_C_SOURCE=199506L'

WBR,
Maris.

Error message:
gcc -I/home/maris/soft/grass-6.2.0RC1/dist.i686-pc-linux-gnu/include  -g -ansi -Wall -D_BSD_SOURCE=1 -D_SVID_SOURCE=1 -D_POSIX_SOURCE=1 -D_POSIX_C_SOURCE=199506L    -fPIC    -DPACKAGE=\""grasslibs"\" -I/usr/include      -DPACKAGE=\""grasslibs"\"    -I/usr/include/ffmpeg/ -I/home/maris/soft/grass-6.2.0RC1/dist.i686-pc-linux-gnu/include 
\
                -o OBJ.i686-pc-linux-gnu/gsd_img_ppm.o -c gsd_img_ppm.c
In file included from /usr/include/ffmpeg/avutil.h:24,
                 from /usr/include/ffmpeg/avcodec.h:14,
                 from gsd_img_ppm.c:19:
/usr/include/ffmpeg/common.h:171: error: expected identifier or ‘(’ before ‘/’ 
token
/usr/include/ffmpeg/common.h:185: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ 
or ‘__attribute__’ before ‘int’
...