gettext-full: set gperf as build prerequisite

Require gperf to be built before gettext.

Signed-off-by: Michael Pratt <mcpratt@pm.me>

package/libs/gettext-full/Makefile

@@ -25,6 +25,8 @@ PKG_FIXUP:=autoreconf
 PKG_INSTALL:=1
 PKG_BUILD_DEPENDS:=gettext-full/host
 PKG_BUILD_PARALLEL:=0
+
+HOST_BUILD_DEPENDS:=gperf/host
 HOST_BUILD_PARALLEL:=0
 
 PKG_SUBDIRS:= \