recipes: Add missing pkgconfig inherit

Various recipes were missing a pkgconfig inherit or pkgconfig-native
dependency despite using pkgconfig.

Add the inherit to igt-gpu-tools/gdb/libmodulemd/libwpe/xwayland/waffle
shaderc/iputils/wpebackend-fdo/lttng-ust/cargo.

(From OE-Core rev: 777d9744570c2dc119dc5d04985896bbb1da5885)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/gdb/gdb-cross-canadian.inc

@@ -1,5 +1,6 @@
 inherit cross-canadian
 inherit python3-dir
+inherit pkgconfig
 
 SUMMARY = "GNU debugger (cross-canadian gdb for ${TARGET_ARCH} target)"
 PN = "gdb-cross-canadian-${TRANSLATED_TARGET_ARCH}"

meta/recipes-devtools/gdb/gdb-cross.inc

@@ -2,7 +2,7 @@ require gdb-common.inc
 
 DEPENDS = "expat-native ncurses-native flex-native bison-native"
 
-inherit python3native
+inherit python3native pkgconfig
 
 # Overrides PACKAGECONFIG variables in gdb-common.inc
 PACKAGECONFIG ??= "python readline ${@bb.utils.filter('DISTRO_FEATURES', 'debuginfod', d)}"

meta/recipes-devtools/gdb/gdb.inc

@@ -1,6 +1,6 @@
 require gdb-common.inc
 
-inherit gettext
+inherit gettext pkgconfig
 
 #LDFLAGS:append = " -s"
 #export CFLAGS:append=" -L${STAGING_LIBDIR}"