we need to include config.h first to know if HAVE_SYS_CAPABILITY_H is enabled or no, otherwise
sys/capability.h is not included and later used
| src/network.c: In function 'can_ping':
| src/network.c:198:2: error: 'cap_flag_value_t' undeclared (first use in this function)
| src/network.c:198:2: note: each undeclared identifier is reported only once for each function it appears in
| src/network.c:198:19: error: expected ';' before 'cap'
| src/network.c:199:2: error: 'cap_t' undeclared (first use in this function)
| src/network.c:199:8: error: expected ';' before 'caps'
| src/network.c:200:6: error: 'caps' undeclared (first use in this function)
| cc1: warnings being treated as errors
| src/network.c:203:2: error: implicit declaration of function 'cap_get_flag'
| src/network.c:203:21: error: 'CAP_SYS_NICE' undeclared (first use in this function)
| src/network.c:203:35: error: 'CAP_EFFECTIVE' undeclared (first use in this function)
| src/network.c:203:51: error: 'cap' undeclared (first use in this function)
| src/network.c:204:17: error: 'CAP_CLEAR' undeclared (first use in this function)
| src/network.c:210:1: error: control reaches end of non-void function
| make[1]: *** [omgps-network.o] Error 1

and -lcap is needed for 2 functions later (should be added only for HAVE_SYS_CAPABILITY_H enabled, but I don't care enough)
| omgps-network.o: In function `can_ping':
| /OE/tmpdir-shr/work/armv4t-oe-linux-gnueabi/omgps-0.1+svnr109-r1/omgps/src/network.c:199: undefined reference to `cap_get_proc'
| /OE/tmpdir-shr/work/armv4t-oe-linux-gnueabi/omgps-0.1+svnr109-r1/omgps/src/network.c:203: undefined reference to `cap_get_flag'
| collect2: ld returned 1 exit status

--- omgps.orig/src/network.c	2009-10-28 18:51:16.000000000 +0100
+++ omgps/src/network.c	2011-05-09 09:59:11.637676772 +0200
@@ -19,16 +19,16 @@
 #include <assert.h>
 #include <glib.h>
 
-#if (HAVE_SYS_CAPABILITY_H)
-#undef _POSIX_SOURCE
-#include <sys/capability.h>
-#endif
-
 #include "config.h"
 #include "util.h"
 #include "network.h"
 #include "customized.h"
 
+#if (HAVE_SYS_CAPABILITY_H)
+#undef _POSIX_SOURCE
+#include <sys/capability.h>
+#endif
+
 /**
  * Ping: reference <Unix network programming>, volume 1, third edition.
  */
--- omgps.orig/Makefile.am	2009-10-28 18:51:17.000000000 +0100
+++ omgps/Makefile.am	2011-05-09 10:04:58.578676679 +0200
@@ -33,7 +33,7 @@
 
 omgps_CFLAGS = $(common_CFLAGS) -O2
 omgps_LDFLAGS = 
-omgps_LDADD = @DEPENDENCIES_LIBS@ -lpython$(PY_VERSION)
+omgps_LDADD = @DEPENDENCIES_LIBS@ -lcap -lpython$(PY_VERSION)
 
 omgps_SOURCES =          \
   src/ctx_agps_online.c  \