boost: only the iostreams library requires bzip2 and zlib

Signed-off-by: Will Wagner <will_wagner@carallon.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/boost/Config.in

@@ -9,8 +9,6 @@ config BR2_PACKAGE_BOOST
 	# that unfortunately doesn't work. Until someone fixes that,
 	# let's depend on threads.
 	depends on BR2_TOOLCHAIN_HAS_THREADS
-	select BR2_PACKAGE_BZIP2
-	select BR2_PACKAGE_ZLIB
 	help
 	  A general purpose C++ library
 
@@ -43,6 +41,8 @@ config BR2_PACKAGE_BOOST_GRAPH_PARALLEL
 
 config BR2_PACKAGE_BOOST_IOSTREAMS
 	bool "boost-iostreams"
+	select BR2_PACKAGE_BZIP2
+	select BR2_PACKAGE_ZLIB
 
 config BR2_PACKAGE_BOOST_LOCALE
 	depends on BR2_USE_WCHAR

package/boost/boost.mk

@@ -12,7 +12,7 @@ BOOST_INSTALL_STAGING = YES
 
 TARGET_CC_VERSION = $(shell $(TARGET_CC) -dumpversion)
 
-BOOST_DEPENDENCIES = bzip2 zlib
+BOOST_DEPENDENCIES =
 
 BOOST_FLAGS =
 
@@ -48,6 +48,10 @@ else
 BOOST_FLAGS += --without-icu
 endif
 
+ifeq ($(BR2_PACKAGE_BOOST_IOSTREAMS),y)
+BOOST_DEPENDENCIES += bzip2 zlib
+endif
+
 BOOST_OPT += toolset=gcc \
 	     threading=multi \
 	     variant=$(if $(BR2_ENABLE_DEBUG),debug,release) \