Revise configure.in to be more sensible.

Reduce the number of header files checked in configure.
Source code doesn't really use the output, and we're linux specific.

Other configure.in parts are fixed to use m4 features rather than
relying on shell features.

configure.in

@@ -1,32 +1,15 @@
 AC_INIT(lsyncd.c)
-PACKAGE=lsyncd
-VERSION=1.0
-AM_INIT_AUTOMAKE($PACKAGE,$VERSION)
+m4_define(LSYNCD_PACKAGE,lsyncd)
+m4_define(LSYNCD_VERSION,1.0)
+AM_INIT_AUTOMAKE(LSYNCD_PACKAGE,LSYNCD_VERSION)
 
 AM_MAINTAINER_MODE
 
 AC_PROG_CC
 AC_PROG_LIBTOOL
 AC_PROG_INSTALL
-AC_CHECK_HEADERS(\
-sys/types.h \
-sys/stat.h \
-sys/wait.h \
-sys/inotify.h \
-stdio.h \
-stdlib.h \
-stdarg.h \
-stdbool.h \
-string.h \
-unistd.h \
-errno.h \
-time.h \
-dirent.h \
-getopt.h
-)
+AC_CHECK_HEADERS([sys/inotify.h])
 
-AC_CONFIG_HEADERS(\
-config.h
-)
+AC_CONFIG_HEADERS([config.h])
 
 AC_OUTPUT(Makefile)