diff --git a/configure.ac b/configure.ac
index f29068e..7c91496 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,4 +26,37 @@ AC_CONFIG_FILES([
   src/Makefile
 ])
 
+# geonames.org support
+AC_ARG_ENABLE(
+    [geonames], 
+    [AS_HELP_STRING([--enable-geonames], [enable support geonames.org geocoding (def=yes)])],
+    [enable_geonames=$enableval],
+    [enable_geonames=yes]
+)
+
+AM_CONDITIONAL([GEONAMES_SUPPORT], [test x"$enable_geonames" = x"yes"])
+if test x"$enable_geonames" = x"yes"; then
+    AC_DEFINE([GEONAMES_SUPPORT], [], [Geonames geocoding])
+    PKG_CHECK_MODULES([DEPS_GEONAMES], [libcurl >= 7.21, json >= 0.9])
+fi
+
+
+AC_DEFINE([GEONAMES_SUPPORT], [1], [compile with geonames.org lookup capabilities])
+
+
+# debug compilation support
+AC_ARG_ENABLE(
+    [debug],
+    [AS_HELP_STRING([--enable-debug], [enable debug data generation (def=no)])],
+    [debug=$enableval],
+    [debug=no]
+)
+
+if test x"$debug" = x"yes"; then
+    AC_DEFINE([DEBUG], [], [enable debugging])
+    AM_CXXFLAGS="$AM_CXXFLAGS -g -Wall -Werror -Wno-uninitialized -O0 -fno-omit-frame-pointer -Woverloaded-virtual -Wno-system-headers"
+else
+    AM_CXXFLAGS="$AM_CXXFLAGS -O3"
+fi
+
 AC_OUTPUT
diff --git a/src/Makefile.am b/src/Makefile.am
index 03eb786..568af56 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,16 @@
-bin_PROGRAMS = sun geonames
+bin_PROGRAMS = sun
 
-sun_SOURCES = sun_main.c sun.c geonames.c
-sun_LDADD = -lm -lcurl -ljson
+sun_SOURCES = sun_main.c sun.c
+sun_LDADD = -lm
 
-geonames_SOURCES = geonames_main.c geonames.c
-geonames_LDADD = -lcurl -ljson
+if GEONAMES_SUPPORT
+  bin_PROGRAMS += geonames
+
+  geonames_SOURCES = geonames_main.c geonames.c
+  geonames_LDADD = $(DEPS_GEONAMES_LIBS)
+
+  sun_SOURCES += geonames.c
+  sun_LDADD += $(DEPS_GEONAMES_LIBS)
+
+  AM_CFLAGS = $(DEPS_GEONAMES_CFLAGS)
+endif
diff --git a/src/sun.c b/src/sun.c
index 5876b26..a2746a3 100644
--- a/src/sun.c
+++ b/src/sun.c
@@ -26,6 +26,7 @@
 #include <math.h>
 #include <stdio.h>
 
+#include "../config.h"
 #include "sun.h"
 
 double deg2rad(double deg) {
diff --git a/src/sun.h b/src/sun.h
index 36132dd..4140ef7 100644
--- a/src/sun.h
+++ b/src/sun.h
@@ -34,8 +34,6 @@ struct coords { double lat, lon; };
 
 struct sun_coords { double dk, ra; };
 
-//#define DEBUG 1
-#define GEONAMES_SUPPORT 1
 #define M_2PI (M_PI * 2)
 
 enum mode { RISE, SET, NOON, DAYTIME, NIGHTTIME };