configure: unify macro naming for optional features

configure

@@ -112,7 +112,7 @@ For better control, use the options below.
   --disable-pps          Disable PPS refclock driver
   --disable-ipv6         Disable IPv6 support
   --disable-rtc          Don't include RTC even on Linux
-  --disable-linuxcaps    Disable Linux capabilities support
+  --disable-linuxcaps    Disable libcap (Linux capabilities) support
   --disable-asyncdns     Disable asynchronous name resolving
   --disable-forcednsretry Don't retry on permanent DNS error
   --with-ntp-era=SECONDS Specify earliest assumed NTP time in seconds
@@ -183,7 +183,7 @@ EXTRA_OBJECTS=""
 EXTRA_DEFS=""
 SYSDEFS=""
 
-debug=0
+feat_debug=0
 feat_cmdmon=1
 feat_ntp=1
 feat_refclock=1
@@ -194,8 +194,8 @@ try_nss=1
 try_tomcrypt=1
 feat_rtc=1
 try_rtc=0
-feat_linuxcaps=1
-try_linuxcaps=0
+feat_droproot=1
+try_libcap=0
 readline_lib=""
 readline_inc=""
 ncurses_lib=""
@@ -215,7 +215,7 @@ for option
 do
     case "$option" in
     --enable-debug )
-      debug=1
+      feat_debug=1
     ;;
     --disable-readline )
       feat_readline=0
@@ -290,7 +290,7 @@ do
       feat_pps=0
     ;;
     --disable-linuxcaps)
-      feat_linuxcaps=0
+      feat_droproot=0
     ;;
     --disable-asyncdns)
       feat_asyncdns=0
@@ -355,7 +355,7 @@ case $SYSTEM in
     ;;
     Linux* )
         EXTRA_OBJECTS="sys_generic.o sys_linux.o wrap_adjtimex.o"
-        try_linuxcaps=1
+        try_libcap=1
         try_rtc=1
         try_setsched=1
         try_lockmem=1
@@ -404,6 +404,11 @@ case $SYSTEM in
     ;;
 esac
 
+if [ $feat_debug = "1" ]; then
+  add_def FEAT_DEBUG
+fi
+add_def DEBUG $feat_debug
+
 if [ $feat_cmdmon = "1" ]; then
   add_def FEAT_CMDMON
   EXTRA_OBJECTS="$EXTRA_OBJECTS cmdmon.o manual.o pktlength.o"
@@ -488,7 +493,7 @@ if [ $feat_ipv6 = "1" ] && \
     n.sin6_addr = in6addr_any;
     return !inet_ntop(AF_INET6, &n.sin6_addr.s6_addr, p, sizeof(p));'
 then
-  add_def HAVE_IPV6
+  add_def FEAT_IPV6
   if test_code 'in6_pktinfo' 'sys/socket.h netinet/in.h' '' '' '
     return sizeof(struct in6_pktinfo);'
   then
@@ -538,17 +543,17 @@ if [ "x$timepps_h" != "x" ] && \
     struct timespec ts;
     return time_pps_fetch(h, PPS_TSFMT_TSPEC, &i, &ts);'
 then
-  add_def HAVE_PPSAPI
+  add_def FEAT_PPS
 fi
 
-if [ $feat_linuxcaps = "1" ] && [ $try_linuxcaps = "1" ] && \
+if [ $feat_droproot = "1" ] && [ $try_libcap = "1" ] && \
   test_code \
-    linuxcaps \
+    libcap \
     'sys/types.h pwd.h sys/prctl.h sys/capability.h grp.h' \
     '' '-lcap' \
     'prctl(PR_SET_KEEPCAPS, 1);cap_set_proc(cap_from_text("cap_sys_time=ep"));'
 then
-    add_def FEAT_LINUXCAPS
+    add_def FEAT_PRIVDROP
     EXTRA_LIBS="$EXTRA_LIBS -lcap"
 fi
 
@@ -659,7 +664,7 @@ if [ $try_nss = "1" ]; then
     HASH_COMPILE="$test_cflags"
     HASH_LINK="$test_link"
     LIBS="$LIBS $HASH_LINK"
-    add_def GENERATE_SHA1_KEY
+    add_def FEAT_SECHASH
   fi
 fi
 
@@ -671,7 +676,7 @@ if [ "x$HASH_LINK" = "x" ] && [ $try_tomcrypt = "1" ]; then
     HASH_COMPILE="-I/usr/include/tomcrypt"
     HASH_LINK="-ltomcrypt"
     LIBS="$LIBS $HASH_LINK"
-    add_def GENERATE_SHA1_KEY
+    add_def FEAT_SECHASH
   fi
 fi
 
@@ -730,7 +735,6 @@ if [ "x$SETCHRONYVARDIR" != "x" ]; then
   CHRONYVARDIR=$SETCHRONYVARDIR
 fi
 
-add_def DEBUG $debug
 add_def DEFAULT_CONF_FILE "\"$SYSCONFDIR/chrony.conf\""
 add_def DEFAULT_USER "\"$default_user\""
 add_def MAIL_PROGRAM "\"$mail_program\""