unbound-control.c:882:6: error: 'execlp' is unavailable: not available on tvOS

[noloader]

Hi Everyone, @wcawijngaards,

I'm testing Unbound Master on iOS. The testing below is on AppleTVOS. WatchOS and the simulators will produce a similar result.

libtool: compile:  clang -I. -I/Users/travis/AppleTVOS-arm64/include -I/Users/travis/AppleTVOS-arm64/include -DSRCDIR=.
-arch arm64 -mappletvos-version-min=6 --sysroot=/Applications/Xcode-10.0.app/Contents/Developer/Platforms/
AppleTVOS.platform/Developer/SDKs/AppleTVOS12.0.sdk -c smallapp/unbound-control.c -o unbound-control.o

smallapp/unbound-control.c:882:6: error: 'execlp' is unavailable: not available on tvOS
                if(execlp("unbound", "unbound", "-c", cfgfile, 
                   ^

/Applications/Xcode-10.0.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS12.0.sdk/
usr/include/unistd.h:442:6: note: 'execlp' has been explicitly marked unavailable here
int      execlp(const char * __file, const char * __arg0, ...) __WATCHOS_PROHIBITED __TVOS_PROHIBITED;
         ^
1 error generated.

We may need to add ac_cv_func_execlp=no to configure. Otherwise, I believe Autotools [incorrectly] guesses execlp is available. (Commit 84864caeefb0 tries the ac_cv_func_execlp=no fix).

This result depends upon PR #187. The 187 PR updates Android and iOS and adds iOS simulator testing to Travis.

Also see Travis test 660761901.

[noloader]

Adding ac_cv_func_execlp=no to configure was not successful. Maybe you can add an Autootools test for the <TargetConditionals.h> header. Then you can add this to unbound-control.c:

#ifdef HAVE_TARGETCONDITIONALS_H
#include <TargetConditionals.h>
#endif

And then disable execlp if TARGET_OS_TV or TARGET_OS_WATCH is defined. Maybe something like:

	if(argc >= 1 && strcmp(argv[0], "start")==0) {
#if defined(TARGET_OS_TV) || defined(TARGET_OS_WATCH)
		fatal_exit("could not exec unbound: %s",
			strerror(ENOSYS));
#else
		if(execlp("unbound", "unbound", "-c", cfgfile, 
			(char*)NULL) < 0) {
			fatal_exit("could not exec unbound: %s",
				strerror(errno));
		}
#endif
	}

This has the benefit of being self sufficient. It does not require users to add ac_cv_func_execlp=no to configure to avoid a wrong guess by Autotools during cross-compiles.

[wcawijngaards]

The commit with the targetconditionals header was imported. The other one with AC_FUNC configure tests is not imported (it looks unused). I removed a whitespace in configure.ac, and remade the configure script. This should import the fixes you had into the master branch on github.

If it does not really work, i.e. after you import it and travis runs, reopen or make a new issue. Thanks for the test and code suggestions!