Makefile: fix LDFLAGS handling

We need these flags to come before all the objects, not after.
Otherwise, flags that impact handling of input objects do not
show up in time.

This also matches standard build system behavior (e.g. autotools).

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Makefile: fix CPPFLAGS handling

This code doesn't respect CPPFLAGS at all.  Fix that and move the
existing -D flags to the right variable.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
sslh-main: fix config_lookup_int call

This func takes an int, not a long.  The current code triggers a warning:

sslh-main.c: In function 'config_parse':
sslh-main.c:275:5: warning: passing argument 3 of 'config_lookup_int' from incompatible pointer type [enabled by default]
     if (config_lookup_int(&config, "timeout", &timeout) == CONFIG_TRUE) {
                                               ^
In file included from sslh-main.c:26:0:
/usr/include/libconfig.h:266:12: note: expected 'int *' but argument is of type 'long int *'
 extern LIBCONFIG_API int config_lookup_int(const config_t *config,

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
drop_privileges: fix setuid check

The code attempts to check the return of setuid, but forgets to assign
the result variable.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
check asprintf return value

The current asprintf usage triggers many warnings like:

sslh-main.c: In function 'print_usage':
sslh-main.c:86:17: warning: ignoring return value of 'asprintf',
	declared with attribute warn_unused_result [-Wunused-result]

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Make version.h before any other object
Merged Makefile LDFLAGS changes