Allow --{enable,disable}-* options to actually work

Multiple tests in configure.ac are flawed:

[--snip--]
    AC_ARG_ENABLE([pthreads],
            [AS_HELP_STRING([--disable-pthreads],
                            [Disable support for pthreads])],
            [pthreads_on=1],
            [pthreads_on=0])
[--snip--]

The third argument is "action-if-given" and the fourth argument is
"action-if-not-given" [0]. Which means that, whether you pass
--enable-pthreads or --disable-pthreads, the third argument will be
executed, that is "pthreads_on=1". And if you pass neither, the fourth
argument will be executed, i.e. "pthreads_on=0".

[0] https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/autoconf.html#Package-Options

Signed-off-by: Aleksandr Makarov <aleksandr.o.makarov@gmail.com>

Author: Aleksandr Makarov

configure.ac

@@ -31,9 +31,9 @@ AM_COND_IF([FREEBSD], AC_MSG_RESULT([Skipping libdl check]),
 AC_ARG_ENABLE([jni], 
 	       [AS_HELP_STRING([--enable-jni],
 			       [Enable support for JNI library])],
-		[jni_on=1],
-		[jni_on=0])
-AM_CONDITIONAL([ENABLE_JNI], [test x$jni_on = x1])
+		[],
+		[enable_jni = "no"])
+AM_CONDITIONAL([ENABLE_JNI], [test "$enable_jni" = "no")
 AM_COND_IF([ENABLE_JNI], 
 	   AC_MSG_RESULT([JNI support enabled])
 	   AC_DEFINE([ENABLE_JNI]),
@@ -43,9 +43,9 @@ AM_CONDITIONAL([JAVA_HOME_SET], [test ! -z "$JAVA_HOME"])
 AC_ARG_ENABLE([client-only], 
 	       [AS_HELP_STRING([--enable-client-only],
 			       [Enable the building of only the client mode of libEST])],
-		[clientonly_on=1],
-		[clientonly_on=0])
-AM_CONDITIONAL([ENABLE_CLIENT_ONLY], [test x$clientonly_on = x1])
+		[],
+		[enable_client_only = "no"])
+AM_CONDITIONAL([ENABLE_CLIENT_ONLY], [test "$enable_client_only" = "yes"])
 AM_COND_IF([ENABLE_CLIENT_ONLY], 
 	   AC_MSG_RESULT([Client only build enabled])
 	   AC_DEFINE([ENABLE_CLIENT_ONLY]),
@@ -54,9 +54,9 @@ AM_COND_IF([ENABLE_CLIENT_ONLY],
 AC_ARG_ENABLE([brski], 
 	       [AS_HELP_STRING([--enable-brski],
 			       [Enable support for brski bootstrap functionality])],
-		[brski_on=1],
-		[brski_on=0])
-AM_CONDITIONAL([ENABLE_BRSKI], [test x$brski_on = x1])
+		[],
+		[enable_brski = "no"])
+AM_CONDITIONAL([ENABLE_BRSKI], [test "$enable_brski" = "yes"])
 AM_COND_IF([ENABLE_BRSKI], 
 	   AC_MSG_RESULT([BRSKI support enabled])
 	   AC_DEFINE([ENABLE_BRSKI]),
@@ -65,9 +65,9 @@ AM_COND_IF([ENABLE_BRSKI],
 AC_ARG_ENABLE([pthreads], 
 	       [AS_HELP_STRING([--disable-pthreads],
 			       [Disable support for pthreads])],
-		[pthreads_on=1],
-		[pthreads_on=0])
-AM_CONDITIONAL([DISABLE_PTHREAD], [test x$pthreads_on = x1])
+		[],
+		[enable_pthreads = "yes"])
+AM_CONDITIONAL([DISABLE_PTHREAD], [test "$enable_pthreads" = "yes"])
 AM_COND_IF([DISABLE_PTHREAD], 
 	   AC_MSG_RESULT([pthread support disabled])
 	   AC_DEFINE([DISABLE_PTHREADS]),