meson: check for libcap via pkg-config

It's possible that setcap is installed, but the libcap headers/libs aren't (e.g.
during cross compilation, when you have the program installed for the host,
but need the headers of the target). Also removes the need to manually check
for the libcap headers.

diff --git a/libs/gst/helpers/meson.build b/libs/gst/helpers/meson.build
index 747cc9e..0f11954 100644 (file)
--- a/libs/gst/helpers/meson.build
+++ b/libs/gst/helpers/meson.build
@@ -64,16 +64,8 @@ if have_ptp
       description : 'getifaddrs() and AF_LINK is available')
   endif
 
-  gst_ptp_have_cap = false
-  cap_dep = []
-  if cc.has_header('sys/capability.h')
-    cap_dep = cc.find_library('cap', required : false)
-    if cap_dep.found() and cc.has_function('cap_init', dependencies : cap_dep)
-      gst_ptp_have_cap = true
-    endif
-  endif
-
-  setcap = find_program('setcap', '/usr/sbin/setcap', '/sbin/setcap', required : false)
+  setcap_prog = find_program('setcap', '/usr/sbin/setcap', '/sbin/setcap', required : false)
+  cap_dep = dependency('libcap', required: false)
 
   # user/group to change to in gst-ptp-helper
   ptp_helper_setuid_user = get_option('ptp-helper-setuid-user')
@@ -90,7 +82,7 @@ if have_ptp
   # how to install gst-ptp-helper
   with_ptp_helper_permissions = get_option('ptp-helper-permissions')
   if with_ptp_helper_permissions == 'auto'
-    if gst_ptp_have_cap and setcap.found()
+    if setcap_prog.found() and cap_dep.found()
       with_ptp_helper_permissions = 'capabilities'
     else
       with_ptp_helper_permissions = 'setuid-root'
@@ -104,8 +96,10 @@ if have_ptp
     cdata.set('HAVE_PTP_HELPER_SETUID', 1,
         description : 'Use setuid-root for permissions in PTP helper')
   elif with_ptp_helper_permissions == 'capabilities'
-    if not setcap.found()
+    if not setcap_prog.found()
       error('capabilities-based ptp-helper-permissions requested, but could not find setcap tool.')
+    elif not cap_dep.found()
+      error('capabilities-based ptp-helper-permissions requested, but could not find libcap.')
     endif
     cdata.set('HAVE_PTP_HELPER_CAPABILITIES', 1,
         description : 'Use capabilities for permissions in PTP helper')
@@ -122,7 +116,7 @@ if have_ptp
 
   meson.add_install_script('ptp_helper_post_install.sh',
       helpers_install_dir, with_ptp_helper_permissions,
-      setcap.found() ? setcap.path() : '')
+      setcap_prog.found() ? setcap_prog.path() : '')
 endif
 
 install_data(['gst_gdb.py', 'glib_gobject_helper.py'],