gdb: add dependency on host-texinfo

Just like binutils, when gdb is fetched from git, it wants to
re-generate its documentation. We were trying to avoid that by patching
the Makefiles, but it wasn't working in all situations.

So, we simply add a dependency on host-texinfo when gdb is fetched from
git, and remove our hackhish work-around.

Fixes:

  http://autobuild.buildroot.net/results/80e63edc009d23cb939880a6f5ae2f220f07a96a/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/gdb/gdb.mk

@@ -11,11 +11,13 @@ GDB_SOURCE = gdb-$(GDB_VERSION).tar.xz
 ifeq ($(BR2_arc),y)
 GDB_SITE = $(call github,foss-for-synopsys-dwc-arc-processors,binutils-gdb,$(GDB_VERSION))
 GDB_SOURCE = gdb-$(GDB_VERSION).tar.gz
+GDB_FROM_GIT = y
 endif
 
 ifeq ($(BR2_microblaze),y)
 GDB_SITE = $(call github,Xilinx,gdb,$(GDB_VERSION))
 GDB_SOURCE = gdb-$(GDB_VERSION).tar.gz
+GDB_FROM_GIT = y
 endif
 
 GDB_LICENSE = GPLv2+, LGPLv2+, GPLv3+, LGPLv3+
@@ -46,18 +48,10 @@ GDB_PRE_PATCH_HOOKS += GDB_XTENSA_PRE_PATCH
 HOST_GDB_PRE_PATCH_HOOKS += GDB_XTENSA_PRE_PATCH
 endif
 
-# Prevent gdb to build the documentation
-define GDB_DISABLE_DOC
-	$(SED) '/^SUBDIRS =/ s/doc//' $(@D)/gdb/Makefile.in
-	if test -e $(@D)/bfd/doc/Makefile.in ; then \
-		$(SED) 's/^INFO_DEPS =.*$$/INFO_DEPS =/' $(@D)/bfd/doc/Makefile.in ; \
-	fi
-	if test -e $(@D)/gprof/Makefile.in ; then \
-		$(SED) 's/^INFO_DEPS =.*$$/INFO_DEPS =/' $(@D)/gprof/Makefile.in ; \
-	fi
-endef
-GDB_PRE_CONFIGURE_HOOKS += GDB_DISABLE_DOC
-HOST_GDB_PRE_CONFIGURE_HOOKS += GDB_DISABLE_DOC
+ifeq ($(GDB_FROM_GIT),y)
+GDB_DEPENDENCIES += host-texinfo
+HOST_GDB_DEPENDENCIES += host-texinfo
+endif
 
 # When gdb sources are fetched from the binutils-gdb repository, they
 # also contain the binutils sources, but binutils shouldn't be built,