tracker-miners: Disable seccomp support on musl

seccomp support piece needs APIs e.g. tgkill which are
unimplimented in musl [1]

Secondly, remove libseccomp from unconditional dependencies
it will be only added when packageconfig is selected.

[1] https://www.openwall.com/lists/musl/2019/08/02/1

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-gnome/recipes-gnome/tracker/tracker-miners_3.7.0.bb

@@ -7,7 +7,6 @@ LIC_FILES_CHKSUM = " \
 
 DEPENDS = " \
     intltool-native \
-    libseccomp \
     tracker \
     zlib \
 "
@@ -43,6 +42,9 @@ PACKAGECONFIG ??= " \
     battery \
     networkmanager \
 "
+# Needs tgkill API which musl does not support
+# see https://www.openwall.com/lists/musl/2019/08/02/1
+PACKAGECONFIG:remove:libc-musl = "seccomp"
 
 PACKAGECONFIG[battery]     = "-Dbattery_detection=upower,-Dbattery_detection=none,upower"
 PACKAGECONFIG[cue]     = "-Dcue=enabled,-Dcue=disabled,libcue"