A video4linux framegrabber Code

Remove useless line defining DEFAULT_CONFIG_FILE

Use ${sysconfdir} if prefix is set

${sysconfdir} default to ${prefix}/etc but can be overwrittent by
--sysconfdir=dir

Fix autoheader warning

autoheader: warning: missing template: SYSCONF_DIR
autoheader: Use AC_DEFINE([SYSCONF_DIR], [], [Description])

Add missing AM_PROG_CC_C_O

Makefile.am:21: compiling `vgrabbj.c' with per-target flags requires
`AM_PROG_CC_C_O' in `configure.in'

Remove extra spaces

Fix compiler warnings

ccvt_c.c: In function ‘ccvt_420i_yuyv’:
ccvt_c.c:471:11: warning: pointer of type ‘void *’ used in arithmetic [-Wpointer-arith]
ccvt_c.c: In function ‘ccvt_420i_uyvy’:
ccvt_c.c:510:11: warning: pointer of type ‘void *’ used in arithmetic [-Wpointer-arith]

Fix compiler warnings

ccvt_c.c: In function ‘ccvt_yuyv’:
ccvt_c.c:256:17: warning: variable ‘linewidth’ set but not used [-Wunused-but-set-variable]
ccvt_c.c: In function ‘ccvt_uyvy’:
ccvt_c.c:353:17: warning: variable ‘linewidth’ set but not used [-Wunused-but-set-variable]

Fix compiler warnings

v_writer.c: In function ‘write_jpeg’:
v_writer.c:63:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
v_writer.c: In function ‘write_png’:
v_writer.c:108:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Fix compiler warnings

v_writer.c: In function ‘write_jpeg’:
v_writer.c:59:13: warning: pointer targets in assignment differ in signedness [-Wpointer-sign]
v_writer.c: In function ‘write_png’:
v_writer.c:110:22: warning: pointer targets in assignment differ in signedness [-Wpointer-sign]

Fix compiler warning

v_utils.c: In function ‘check_maxlen’:
v_utils.c:324:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]